ok im kinda new to this computer thing but i bought a dell from a friend and took it home and set it up. it boots just fine into windows xp but my mouse and keyboard does not work. i tried two difrent mouses and keyboards and also used an ometer on the connection and there is power going to it. please help.....

Are your mouse and keyboard attached by a PS2 (round, multi-pin) or USB? The computer may have been set up for the opposite type of mouse and keyboard.
Try pressing [Windows], move to Settings, then Control Panel, then Add New Hardware. This should detect your mouse and keyboard. If successful, re-boot. The mouse and keyboard should work.
If not, navigate by Windows key, then arrows to Control Panel, then System. Under mouse and keyboard, uninstall the current mouse and keyboard drivers. Then run Add Hardware again. Re-boot if successful.