Hopefully the keyborad is PS2. Re-boot and tap the F8 key to enter safe Mode. Once there use the device manager to uninstall any and all USB entries then reboot, Try the USB ports again, post back on the results.
I have a dell dimension 8250 with windows xp home addition. I had a dell aio a940. It kept giving me systems error so I uninstalled it and got a dell aio printer 962. Installed it. Now I have no live usb ports. I have six in back and two in front and all are dead. I lost my mouse & had to hook it up to the old style connection usb won't work. I tried my system restore and my computer wont restore. It keeps telling me it can't go back. I went to devices and my usb tells me there is no problem. I do have some usb that show a yellow ?. Is it possible that I have to replace all my usb cards.