Hi guys, this is the strangest problem I've seen in my 15+ years of being a techie!!!
I have a new pc with a Gigabyte GA-H67MA-UD2H-B3 motherboard and I plugged a Microsoft 600 Wired Keyboard into the rear port (designated for KB/Mouse by Gigabyte). The keyboard works in the BIOS, but when Windows 7 loads, the num lock light switches on, then Windows 7 says that "Driver not installed properly". In the Devices & Printers window, it shows an icon of the keyboard with a yellow exclamation mark and says "hadware not available". However, mouse continues to work.
This happens in all the rear USB ports. If I plug the keyboard in the front port, Windows recognizes the keyboard, install the correct driver and it works! All the USB ports work fine otherwise (tested with thumb drive as well as mouse).
I also tried with a Logitech K120 wired keyboard which also had the same problem. Any ideas on why this is happening? I've been solving PC issues for the last 15 years and still I'm stumped!!!
I solved the problem. It was caused by a USB audio device m-Audio Fast Track Pro which is a USB 1.1 based device. Whenever Windows 7 detected the audio device first, the keyboard would not be detected. If I disconnect the audio device, and start windows, the keyboard would be detected and if I reconnect the audio device after the keyboard has been detected, it would also work.
Somehow, if Windows detected the audio device first, it prevented any USB keyboard from working. There is no other solution to this other than making sure that the audio device is disconnected first and reconnected last.