You didn't say who the manufacturer of your mouse and keyboard is. I had this problem with Logitech keyboard and mouse hardware. No matter which one I used they would freeze/lock-up. I tried other manufacturer's hardware before returning to Microsoft hardware. I have not had any problems since then.
I personally know others that have had the same problem with Logitech hardware. I often warn people not to buy Logitech keyboard or mouse hardware unless they have used it successfully in the past. I have contacted Logitech numerous times about the problems but so far they have not found a solution. Therefore, I now rely on Microsoft hardware.
My mouse and keyboard functions freezes within an hour of startup. I have a biostar u8668 pro motherboard, intel p4 1.7ghz, 512 ddr ram, cd and dvd writers and two hard drives. I am running windows xp pro with all the service packs and upgrades. I even flashed the bios with no apparent improvement. On immediate rebooting all is well for about the same time before it freezes again. What am I overlooking? Thanks for any pointers.