|The ONLY bios setting that has anything to do with your problem...|
The USB controllers MUST be enabled in the bios. They are are by default.
Do you have a bootable disk such as an XP CD you can boot the computer from?
If yes, boot the computer from that. If a corded keyboard or mouse doesn't work with that, when plugged into a USB port physically built into the mboard on the back of the case, your computer has a hardware problem.
I'm assuming that if you have USB devices plugged into ports in the desktop case, or ports in a wiring adapter installed in a slot space on the back of the case that has a plate with USB ports, that they are connected properly to the pins on USB headers on the mboard.
Have you been fiddling with wiring connections to that / those USB headers ?
The correct way to wire them up is shown in the manual for the retail mboard model if you have a generic system. For a brand name system, you may need to refer to a manual for a retail mbord model made by the same mboard supplier at about the same time.
If you connect the wire for +5v to the ground pin for the +5v circuit by mistake, the USB port will NOT work and anything you plug into that mis-wired port will be DAMAGED instantly, at least it will be if the computer was running at the time. .
NOTE that some mboards - e.g. many Asus models - have one or more headers on the mboard that are for a single firewire port that have a header that is physically identical to that for two USB ports - 9 pins, 4 in one row, 5 in the other, a pin missing in the same corner. The plastic at the base of the two types of headers is usually a certain color depending on what it's used for.
If you connect the wiring for a firewire port to a header for two USB ports, or the wiring for one or two USB ports to a firewire header, whatever you plug into the mis-wired port, at least while the computer is running, will NOT work, it will be instantly damaged, the circuits for the port(s) will be damaged in a very short time, and the circuits of the mboard may be otherwise damaged in a short time.
Simple devices such as corded keyboards and mice should work when plugged into any USB port.
Drive letters / Icons for USB devices do NOT show up in My Computer unless Windows has detected the device properly, and they don't show up there for USB devices that have no data storage capability - e.g. keyboards, mice, printers, all in ones, cameras, scanners.
Cameras require that drivers, or at least one program for the camera which may include the camera drivers, be installed for the camera BEFORE they are first plugged in.
MP3 players and memory card readers MAY require that drivers be installed for it BEFORE it's first plugged in.
Drive letters / Icons for external hard drives
- will NOT show up.....
- if the USB port it is plugged into cannot actually supply 500 ma of current
- if hard drive has no data on it that Windows recognizes, or if it does have data on it but it's been damaged, which is COMMON.
- may NOT show up in any case......
- if the external hard drive is plugged into a USB port in an external USB hub,
- or into a USB port on the front of a desktop case
Troubleshooting USB device problems including for flash drives, external drives, external memory card readers.
See Response 1:
In addition to that info....
For some desktop mboards you can have problems when an external hard drive is plugged into one of a pair of USB ports on the back of the case that are connected to the same USB controller, if there is another device plugged into the other USB port for the pair, because the pair can't actually supply 500 ma per port - they can only supply 500 ma in total. Usually those pairs of ports are one above the other, not beside each other. If you have two devices plugged into such a pair of ports, try plugging one of them in elsewhere on the back of the computer.