For the last 2 weeks I've been having problems with the keyboard and mouse that are plugged into the ps/2 ports. I fixed the issue with the mouse by moving it to a USB port, but the keyboard is still on the other ps/2 port. The keyboard is fine/good and have even tried 2 other keyboards (new) on the ps/2 port and the problem is still there. Have uninstalled the driver and re-installed, no help.
Here's the problem, at times when I press a key, the alarm on the motherboard starts to sound continuously, at times it'll go on for minuets and the keyboard will quit working. (It has nothing to do the mobo temps, have already checked that area...) The alarm will even continue as I'm shutting it down. If I remove the keyboard before a reboot, I have no problem what so ever, just the lack of a keyboard, I have to use the On-Screen Keyboard in XP to type...
I tried using a keyboard with a USB adapter at the end, but my PC will not recognize the keyboard. I checked the BIOS to enable that option if there was an option under the BIOS, but I didn't see anything relating to enabling USB/keyboard support under the BIOS... (Using latest BIOS, may have to go back to an older version, because I believe I've seen an option to enable USB Keyboard support on the previous BIOS version I had.) Any clues???

The motherboard is an ASUS A7N266-E and has been in full operation for 6 years. OS is Win XP Pro SP2.