I'm not sure which category this should be under so I just picked one. We have a Dell Dimension 3000 that is used as a backup computer. However, just recently it's not recognizing any keyboard or mouse plugged into the usb ports. We've tried each port but to no avail. What would cause this? Is this something that I would have to have it serviced? For financial reasons, I'm hoping not. Any help or suggestions would be greatly appreciated.