I have a D-Link G604T Modem/Router and ADSL light blinks after I have a phone call and wont log on to Internet.

Reset and than re install internet provider settings

Try to pull the wires and restart your modem if there are no changes you should ask fof techy assistance

if the speed was upgraded to ADSL 2 you need ADSL filters that match this. Check the model number of the ADSL filters and check the type of DSL is compatible with the Speed change.

Hi ! If it is your only computer Make sure the you use ADSL filters not only on your router to phone line connections but also on every phone you use. If you have any other computers on your network please explain how they are connected and what OS do they use?

1.Make sure there are no problems with your network card and cable.
2. Run cmd and go to command line
3. Run ipconfig
4. Your router's IP is Default gateway, if it different from 192.168.1.1 you router address was changed and you must access to new one
5. If it 192.168.1.1 try to ping it. If no ping here, your router probably broken
6. This behavior may happens also if router overheated

Detail tutorial about how to find router address:
http://www.routercommander.com/help/howto#telnet_setup

If the Internet light is off then there is a problem with the phone line to the ADSL modem or the modem is faulty or there is a problem at the telephome exchange.
Disconnect the phone cable at the ADSL modem and connect a phone handset to this cable - check for a dial tone and that you can dial out.
If you don't get a dial tone, use a different or new phone cable.
If the phone line is OK then : -
Ring your ISP to get them to test your connection to your ADSL
modem.

I think the light that blinks is the light that shows when you have a connection established to your ISP. Not sure if you have cable or ADSL but if the light is blinking then the router is Synchronising with the line card at the ISP/exchange end. If it continues to blink then no sync is occurring. If ADSL replace the microfilter and check that any devices atached to that line also have a microfilter between them and the socket. ALso try replace the phone cable to the microfilter to the socket. Finally you can see wether sync has occurred by looking in the log on the router
Hope this helps

Mark

when the adsl is not blinking that means your phone line is having problem plz ask your phone line provider to check the line.

You can try something to narrow down where the problem is. Plug your pc directly into your modem and unplug your router altogether. This will not allow you to use you other computers on the internet. Don't worry you only have to do this for 4 or 5 hours. If the pc remains on net and you have no glitches then you might want to think about getting a new router. Since the router worked fine for 8 months, I wouldn't think the settings got changed. Routers aren't perfect pieces of equipment, I have had to purchase 3 in 4 years.

all ADSL routers are very fussy when it comes to power fluctuations, even the tiniest can set them into error, first thing to try, is pull the power cord out of the back of the modem, wait a couple of minuteds, then plug it back it, give it a few moments to re-connect and see how it is, if no luck with that, check the DSL, or ADSL light is on and solid.. if so look on the bottom of the modem for an ip address, open internet explorer browser, type that ip address into the address bar and hit enter, it should prompt you for a username and password.. usually ADMIN for both user and pass.. then go to "status" or "diagnostics" depending on the modem, and it will give you a run down on any potential problem..

PPP error: username and password are wrong (Authentication Failure)