The firmware upgrade failed and i cannot access the router anymore...need to restore without having access to the ip address

How many computers do you have in the network?
How many are not able to access the Internet or IP address?
If only one computer is not able to access the Internet then you can try assigning a static IP address on the computer and see if you can access the Internet.
If all the computers are not able to get IP address from the router then I think you should try to reset and upgrade the firmware on the router.

See How to upgrade firmware on Linksys router.

You have to manually assign a compatible IP address on your PC which you used to update the router in order to access it. For example, if the router default is 192.168.1.254, then you have to assign the PC 192.168.1.200 (IP address), 255.255.255.0 (subnet), 192.168.1.254 (gateway) on the PC. You should be able to get in the flash the 2nd and 3rd parts of the firmware. After completing the firmware flash, do a factory reset on the router and you should re-configure it again by hand. Good luck!

Check this tip out from Linksys. It is for a G VPN Router but you could use the same steps to troubleshoot. Title: Resolving Blinking Power or Diag LED on a Linksys Wireless-G VPN Router Article ID: 4982 If the Power LED on your Linksys router is blinking, this means the device is not ready. It should go off once the router completes its diagnostic test. If the Power LED won?t go off, it indicates that there?s a possible hardware problem with the router. To resolve this, you will need to perform five steps: Resetting the Router Assigning Static IP to the Computer Pinging the Router Accessing the Router?s Web-based Setup Page Updating the Router?s Firmware For instructions on how to reset the router, follow the steps below. Resetting the Router Hold in the RESET button at the back of the router for 30 seconds. Unplug the power to the router then plug it back in. If after resetting the router and the Power LED is still blinking, try resetting the router again for another 30 seconds. Then proceed with assigning a static IP address on the PC. For instructions, follow the steps below. Assigning a Static IP Address on Your Computer Most of the time, if the power LED on the router is blinking it loses its ability to assign IP addresses to the PCs connected to it, which is why you need to assign the computer a static IP address. After assigning a static IP address on the computer, check if the computer is still communicating to the router by performing a ping test. To ping the router, follow the steps below. Pinging the Router Ping test helps trace the communication between the computer and the router. The computer sends packets to the router and in return the router sends out replies to validate the connection. In this example, our router IP address is 192.168.1.1. NOTE: If you?re using Windows 98 or ME, click here. Windows 2000/XP Step 1: Click Start, then Run. Step 2: When the Run window opens, type ?cmd? in the Open field, then click OK. Step 3: When the MS DOS Prompt appears, type ?ping 192.168.1.1? and press [Enter]. Step 4: Check the ping statistics. You should get Packets: Sent =4, Received =4, Lost = 0 (0% loss). NOTE: If you?re not getting good replies from the router, it means the router is not communicating properly with the computer anymore. You can already consider the device defective. Windows 98/ME Step 1: Click Start, then Run. A window similar to Step 2 will appear. Step 2: When the Run window appears, type ?command? in the Open field, then click OK. Step 3: When the MS DOS Prompt appears, type ?ping 192.168.1.1? and press [Enter]. Step 4: Check the ping statistics. You should get Packets: Sent =4, Received =4, Lost = 0 (0% loss). NOTE: If you?re not getting good replies from the router, it means the router is not communicating properly with the computer anymore. You can already consider the device defective. If you get good responses from the router, access the router?s web-based setup page to see if a firmware update is possible. For instructions, follow the steps below. Accessing the Router?s Web-based Setup Page In order to perform a firmware update, you should be able to access the router?s web-based setup page. Updating the firmware is one way of resolving the blinking power light on the Linksys router. To access the router?s web-based setup page, click here. NOTE: If you?re having difficulties accessing the router?s web-based setup page, the router is considered defective. If you?re able to access the router?s web-based setup page, proceed in updating the firmware upgrade.

Base from the description of your problem that you need to restart the router in order for the connection to work again its clear that the problem here is with the router.So what we need to do here is to do a firmware upgrade on this router to get the latest firmware for your router you can go to Dlink.com and download the firmware there.

Then once you have the firmware of the router you need to access the router setup page to load it to it.
Open a web browser like internet explorer or Netscape. Enter the ip address of your router in the address bar of your browser. By default the ip address should be set to 192.168.0.1.
By default the username is Admin, and the password is blank. Click the Log In button to log in to your router.

From there look for the firmware upgrade option and then you can ow continue with it and once you're done with the upgrade observe the connection and that should be fine now.

You might want to check your firmware version to make sure you have the lastest.

BETA Firmware Version 3.93.35.0.9This firmware fixes the following issues:

• Printing issues with CUPS version 1.2.

USR5461a-v4.3.93.35.09.usr 1.8 MB 06-05-08

Firmware Version 3.93.35.0.8This firmware fixes the following issues:

• DST (Daylight Saving time) Firewall issue with how IAC (Internet Access Control) works.
• PPPoE server disconnect/reconnect
• PPPoE inactivity timer
• PPTP client disconnect/reconnect
• backup/restore settings

Note: If upgrading from Version 3.91.37.0.3, follow these instructions before proceeding.

1. With a thin tool, such as a paper clip, briefly press the RESET button on the back of the router.
2. Wait about 30 seconds.
3. Continue with instructions below.

Important: To ensure a successful upgrade, please perform the firmware upgrade from a client that is physically wired to the router. A wireless client may become disassociated from the router during the upgrade process resulting in an incomplete upgrade.

1. Download this file to a temporary location on your computer's hard disk drive.
2. To upgrade your USRobotics Wireless MAXg Router with all operating systems, open an Internet browser and enter the router's IP address. The default IP address of the router is 192.168.2.1
3. Enter your User name and Password. Click OK.
4. Click Device in the main menu.
5. Under the "Upgrade Router" section, enter the location of the USR5461-v3.93.35.0.8.usr file in the text box, or click the Browse button to search for the file. Then click the Upgrade button to begin the upgrade process.
6. When the upgrade process is complete, the router will reboot. To re-establish a connection with your router, wait approximately 15 seconds and click Continue.

USR5461-v3.93.35.0.8.usr 1.8 MB 10-25-06

There might be a reason that the default gateway of your router and the internet are same.So first connect your router to any one of the computer and open the router page by typing 192.168.1.1 (username should be left blank and password-admin).Then on the basic setup page change the Local IP address to 10.10.10.1,scroll down and click save settings.Now power off your router and connect internet cable to internet port of the router.Switch on the power of router and now try to go online. If you are unable to go online then connect your computer directly to the modem and download the new firmware from www.linksys.com/support and connect your computer then to the router,upgrade the firmware of the router and try to go online by connecting internet cable.

Here's what you need to you may need to reset the router first if you want to access the router setup screen (default settings),

resetting the router - have a paper clip and push the button there for 30 sec. turn off the router and turn it back on.

checked the IP address also of the computer, click start run CMD and hit okay. Then push IPCONFIG and check it the IP address, you should be getting 192.168.1.100 for the IP address and default gateway of 192.168.1.1..

Let me know what happens there..

Verify 1st if you can still communicate with the router, if your running WIndows go to the command prompt and type ipconfig, check your default gateway address(192.168.x.x) then type ping(space)192.168.x.x if your getting replies your still lucky that means the firmware was just incomplete and to complete this without accessing the configuration utility, you need a tftp server installed on yuor computer to load the firmware of the router, check if your router manufacturer has a recommended tftp server, if not download any tftp server software from 3rd party manufacturer such as linksys or netgear, dlink. When you open the tftp software it will normally prompt you to enter the following information - ip address of the device you want to upgrade, password and the ocation of the file you need to load on the device(in this case the firmware(.bin) that you downloaded).

Hope this will help you get your router uo and running,

Regards.

What are you using for Internet connects? do you have the Access point connected to a Router. or is it connected to the Cable or DSL modem. I will need more information to complete this. If you have a router is is set to give an IP address or do you have a static IP? If it is set to give a Dynamic ip change the access point to recieve ip address from router and same with computer. If your connected directly to the Modem with the access point and you only have one IP address it will be used by the access point and not allow the computer to connect.
for more help please provide your internet (DSL, T1, CABLE) if you have router,  how it provides IP, and how access point is connected to it.

What is Management Mode? If you encounter an irrecoverable condition with the WRT54G v5, you can use Management Mode to recover the router by uploading a new firmware image. In Management Mode, the router will have just enough functionality to load a newer firmware. You should be able to recover the router is most situations. When will the WRT54G v5 enter Management Mode? The WRT54G v5 will enter Management Mode when: * The router's firmware is corrupt (for example, when the router's Power light is blinking), OR * When the router has been reset incorrectly using the following steps: 1. Unplug the power cord. 2. Press and hold the Reset button. 3. Plug power cord back in (Reset button still held in). 4. Wait about 5-10 seconds. How do I get out of Management Mode? * To get out of Management Mode, simply unplug the power cord from the back or router for ten (10) seconds and plug the power cord back in (without using the Reset button). If the router's firmware is complete and without error, the router will start up normally. If the above does not work, try: * Download a local copy of WRT54G Version 5 firmware that you can use for recovery. Visit http://www.linksys.com/download to download the latest firmware. After unzipping and extracting the firmware file, click on the Browse button from the Management Mode page, select the firmware file, and upgrade the firmware. After this, Reset the router normally (by holding in the Reset button for 10 seconds) and the router should exit Management Mode. How do I enter Management Mode manually to recover my router? NOTES: * The PC that will be used for the recovery MUST be connected to the router via a hardwired Ethernet cable and not a wirelessly connected computer. * Be sure that you have a local copy of WRT54G Version 5 firmware that you can use for recovery. Visit http://www.linksys.com/download to download the latest firmware. * In most cases, the router will be able to provide an IP address via DHCP when in Management Mode. If your PC does not automatically receive an IP address from the router, you will have to set up a static IP address for the upgrade. See Answer ID 534 for more information. * When the router is forced into Management Mode, the Power light will blink. 1. Unplug the power cord from the back of the router. 2. Hold down the Reset button. 3. While holding down the Reset button, plug back in the power cord to the router. 4. Continue to hold the Reset button for five (5) seconds. After five (5) seconds, release the button. 5. Wait for about one (1) minute. Then, on a computer connected to the router, launch a web browser (for example, Internet Explorer or Mozilla Firefox). 6. Type in the router's IP address of http://192.168.1.1 into the Address field and press the [Enter] key. 7. The Management Mode - Firmware Upgrade interface should appear. NOTE: If you accidentally enter into Management Mode, you can exit by simply unplugging the power cord from the router and by plugging it back in. 8. Click Browse and locate the firmware file. 9. Click Apply to start the firmware upgrade process. 10.Once the firmware upgrade process has successfully completed, an "Upgrade Success" message will appear to confirm that the upgrade has ended. 11. Unplug the power cord from the back of the router and plug it back in -- this will restart your router using the new firmware.