Usb problem I cannot use my keyboard and mouse at the first starting computer. What is the problem?

Are these wired or wireless, USB or PS2 connections..

PS2 Connectors should only be worked when the computer is Turned Off
USB can be Hot Swapped..

If USB try another USB port ..If PS2 make sure they weren't swapped by accident
Check your BIOS
Try another another Keyboard / Mouse

when you turn on the mouse and if you have the USB transmitter in your USB port, the computer should automatically detect the mouse and the keyboard, (make sure both the keyboard and the mouse are switched on otherwise the computer will not see it. also be sure that your batteries are new (or check them with a volt meter). you don't actually do anything called "sync" with the mouse or keyboard.

There are 4 possible ways in my awareness...
Method 1: Resynchronize your device with the receiver To resynchronize the mouse or the keyboard with the receiver, follow these steps. Note When you synchronize the mouse or the keyboard with the receiver, put the device near the receiver and put any other wireless keyboards and mouse at least 6 feet away.

1. Press the button on the receiver, and then verify that the light on the receiver starts to blink.
   
   Note Some newer Microsoft devices are permanently bound to their receiver and cannot be reset. If your device does not have a button, skip to Method 2.
2. If a dialog box appears on the screen in several seconds, follow the instructions that appear on the screen. Otherwise, go to the next step.
3. Press and release the Connect Channel button on the bottom of the mouse or the keyboard.
4. Check the green light on the receiver. A steady green light means the synchronization was successful. If the problem persists, try steps 1 through 4 again.
5. For the Wireless Notebook mouse: This issue can occur if the micro-switch on the bottom of the mouse is not released. Use a pin or a pen to try to release the button if it is depressed.

The following example shows the buttons to push to synchronize a wireless hardware device:

Receiver Bottom of the mouse: The connect channel button Different kind of receiver Collapse this imageExpand this image Collapse this imageExpand this image Collapse this imageExpand this image Method 2: Try different portsTo determine whether the problem is related to the ports on the computer, use only the two cables that are included with the wireless desktop receiver, or the single cable that is included with a mouse. USB keyboard and USB mouseIf the USB cable is currently connected to a USB hub, disconnect the device from the hub, and then connect it to a USB port on the computer. If your device is already connected to a USB port on the computer, try to connect the device to a different USB port if one is available.

Note Only one USB connection to the computer is required, even if your device has two USB plugs. If the problem persists, disconnect other USB devices and connect only the USB plug from the receiver to a USB port on the computer. PS/2 devices Warning If you have to change a PS/2 connection, shut off the computer, make the changes, and then restart the computer. Do not plug a PS/2 device into the PS/2 port while the computer is running.If your devices are connected to PS/2 ports on the computer, verify that you have the following configurations:

• Verify that the USB plug for your mouse is connected to the green USB-to-PS/2 adapter and that this adapter is plugged in the mouse PS/2 port on the computer. The mouse PS/2 port on the computer may also be green. If you are not sure which PS/2 port is the mouse PS/2 port, see the documentation that was included with the computer.
• Verify that the USB plug for the keyboard is connected to the purple USB-to-PS/2 adapter and that this adapter is plugged in the keyboard PS/2 port on the computer. The keyboard PS/2 port on the computer may also be purple. If you are not sure which PS/2 port is the keyboard PS/2 port, see the documentation that was included with the computer.

If you have to change your configuration, shut down the computer, make the changes, and then restart the computer. If your mouse or keyboard has both USB and PS/2 connections, try using the other connection. PS/2 keyboard and USB mouseIf you are using a wireless mouse with a USB connector and a PS/2 keyboard, verify that the USB mouse is plugged in a USB port on the computer and that the purple keyboard PS/2 plug is connected to the purple PS/2 port on the computer. If you have to change the PS/2 connection, shut off the computer, make the changes, and then restart the computer. Method 3: Reinsert the batteries or install fresh batteriesBoth the wireless keyboard and the wireless mouse rely on AA alkaline batteries for power. Remove the batteries, and then insert them again. If the problem persists, install a fresh set of batteries in the device that you are having problems with. Method 4: Check for interferenceItems such as wireless routers, radios, cell phones, desktop fans, fluorescent lights, and large metal objects like computer cases and metal furniture may interfere with the signal of the keyboard. Try to keep such items away from the keyboard, and check the behavior of the keyboard.

Do not put the mouse or the receiver near any electrical devices, especially transmitters such as cordless or cellular telephones or other wireless mouse devices or receivers. A distance of at least 8 to 12 inches is recommended. Do not put the mouse or the receiver on metallic surfaces or objects, especially long metallic rails or cables. We recommend that you keep the mouse and the keyboard a minimum of 3 feet from metallic objects.

1.
If the underside of the mouse has an on/off switch, make sure to set the switch to the "On" position.
2.
Restart the computer. This can resolve the problem, at least temporarily, so that other troubleshooting steps can be applied.
3.
Move the mouse or keyboard closer to the receiver
The receiver is the hardware that receives the wireless signals from the keyboard and mouse and communicates the data to the computer. Most receivers connect to a USB port, either directly or by a cable, but a few types of receivers connect to the PS/2 ports.
. Make sure that the keyboard and the mouse are within 100 centimeters (39 inches) of the receiver. If the receiver is attached to a cord, position it so that it is on the same level surface, close to the mouse and keyboard.

4. Replace the batteries with a fresh set of alkaline batteries and make sure they are correctly installed. If the mouse or keyboard is not working, then replace the batteries, even if the mouse/keyboard software indicate the batteries still have a charge.
Remove the battery cover to access the batteries. For keyboards, the battery access cover is found on the underside of the keyboard. When replacing the batteries look for the positive symbol (a plus sign +) imprinted near the battery compartment or battery cover. Make sure the positive end of the battery is oriented to the positive side of the compartment.

5.
If you have a USB receiver, unplug the USB receiver, wait 10 seconds, and then insert it into another USB port - preferably into a USB port that is closer to the mouse and keyboard. For example, if the USB receiver was plugged into a USB port on the back of the computer, unplug it and plug it into a front USB port.
6.
Resync the wireless keyboard and mouse connections.

Resync the keyboard and mouse connections for receivers with a connect button .
Resynchronizing the keyboard and/or mouse causes the devices to reconnect to the receiver using new identification numbers.
NOTE: The following connection sequence must be completed within 60 seconds. If the sequence is not done in 60 seconds, start over.

Yes turn off your computer and replace the Cmos battery. It seems that your keyboard and mouse is connected into the usb port of your computer, the usb function in the Cmos setup is disabled that's why your keyboard and mouse is not working. Upon checking the Cmos setup enabled the usb function and save the changes and restart the computer to take effect.

Are the batteries fresh in the keyboard and mouse? Do you have USB keyboard and mouse to try (to eliminate possibility of wireless keyboard / mouse failure) If you do have alternate (USB or PS/2) keyboard and mouse, make sure and unplug the USB receiver for wireless set before testing. Let me know results.

if the keyboard and mouse where usb try a ps/2 keyboard and mouse,
The cable probably shorted out the usb ports on your computer,
do any other usb devices work on your pc???

I solved this problem by
1taking off the tower cover

Mice and keyboard are the two most basic input devices for the modern computer. Not much is needed to change them out.

Turn your computer off. Remove the old keyboard and mouse. Connect the new keyboard and mouse into an available usb port. Restart your computer.

You may have to wait anywhere from 30 seconds to a few minutes, depending on your computer, before the operating system recognizes the new hardware, but once it does, it will start responding.

wireless keyboards and in wireless mouse devices, use the following methods in the order that they appear in.

Method 1: Try different ports loadTOCNode(2, 'moreinformation'); Warning If you have to change a PS/2 connection, shut off the computer, make the changes, and then restart the computer. Do not plug a PS/2 device in the PS/2 port while the computer is running.

To determine whether the problem is related to the ports on the computer, use only the two cables that are included with the wireless desktop receiver, or the single cable that is included with a mouse.
USB keyboard and USB mouse loadTOCNode(3, 'moreinformation'); If the USB cable is currently connected to a USB hub, disconnect the device from the hub, and then connect it to a USB port on the computer. If your device is already connected to a USB port on the computer, try to connect the device to a different USB port if one is available.

Note Only one USB connection to the computer is required, even if your device has two USB plugs. If the problem persists, disconnect other USB devices and connect only the USB plug from the receiver to a USB port on the computer.
PS/2 devices loadTOCNode(3, 'moreinformation'); If your devices are connected to PS/2 ports on the computer, verify that you have the following configurations: • Verify that the USB plug for your mouse is connected to the green USB-to-PS/2 adapter and that this adapter is plugged in the mouse PS/2 port on the computer. The mouse PS/2 port on the computer may also be green. If you are not sure which PS/2 port is the mouse PS/2 port, see the documentation that came with the computer. • Verify that the USB plug for the keyboard is connected to the purple USB-to-PS/2 adapter and that this adapter is plugged in the keyboard PS/2 port on the computer. The keyboard PS/2 port on the computer may also be purple. If you are not sure which PS/2 port is the keyboard PS/2 port, see the documentation that came with the computer.If you have to change your configuration, shut off the computer, make the changes, and then restart the computer. If your mouse or keyboard has both USB and PS/2 connections, try using the other connection.
PS/2 keyboard and USB mouse loadTOCNode(3, 'moreinformation'); Verify that the USB mouse is plugged in a USB port on the computer and that the purple keyboard PS/2 plug is connected to the purple PS/2 port on the computer. If you have to change the PS/2 connection, shut off the computer, make the changes, and then restart the computer.

Method 2: Install fresh batteries loadTOCNode(2, 'moreinformation'); Both the wireless keyboard and the wireless mouse rely on AA alkaline batteries for power. If the problem persists, install a fresh set of batteries in the device that you are experiencing problems with.

Method 3: Resynchronize your device to the receiver loadTOCNode(2, 'moreinformation'); To resynchronize the mouse or keyboard to the receiver, follow these steps.

Note When you synchronize the mouse or the keyboard with the receiver, put the device near the receiver and put other wireless keyboards and mouse more than six feet away. 1. Press the button on the receiver, and then verify that the light on the receiver starts to blink. 2. If a dialog box appears on the screen in several seconds, follow the instructions that appear on the screen.

Otherwise, go to the next step. 3. Press and release the Connect Channel button on the bottom of your mouse or keyboard. 4. Check the green light on the receiver. A steady green light means the synchronization was successful. If the problem persists, try steps 1 through 4 again.

Clean the mouse lens loadTOCNode(2, 'moreinformation'); This problem may occur if you are using an optical or laser mouse and the lens on the mouse is dirty. To clean the lens of an optical or laser mouse, follow these steps: 1. Use a dry cloth to clean the bottom surface of the mouse. 2. Check to see whether the mouse functions correctly. 3. If you see dust on the bottom of the mouse, use a can of pressurized de-ionized air to blow away the dust on the lens. 4. Check to see whether the mouse functions correctly. 5. If the pressurized air canister is not available, blow dry air on the lenses by using your mouth one or two times. 6. Check to see whether the mouse functions correctly. 7. If these steps do not resolve the problem, use a cotton bud to clean the lens without scratching it.