I've seen this with two causes.
1. The BIOS was out of date.
2. Drivers for some mouse or keyboard were installed. I uninstall such.
The system works perfectly with this exception. This started after installing XP Pro on separate partitions of the HD. I have reinstalled the OS to each patition without any change. It still only recognizes the keyboard and mouse on every other startup (everything else appears normal after boot, just a frozen mouse cursor and a nonfunctioning keyboard). WHY would this happen and how in the blank can I fix it? Any help is very much appreciated.