HP Pavilion ze2113us freezes. No blue screen, no errors, mouse and keyboard stop

Hi all.

New to forum so please bare with me if I violate anything. I have an HP Pavilion ze2113us that has a formatted hard drive, new istall of XP, new heatsink and working fan, good battery, charger, tested memory and all the latest drivers. The problem is that after about 8-10 minutes, the mouse and keyboard stop working and I have to do a hard reboot only for it to happen again. It just freezes. Windows update balloon and other things still load in system tray while the mouse and keyboard do not work.

I am a computer tech but this one has me stumped. At first I thought it was over heating because I noticed that the fan did not work, so I replaced it with a working fan and heatsink. I swapped out the memory sticks, still it happens. There are no errors, blue screens, errors in event log or smell or feel of excessive heat on the bottom of case.

I would look at the touchpad and keyboard but initially they work fine. Only after 8-10 minutes do they stop working. Still seems to me like an overheating problem but the laptop should shut down or reboot when that happens. It does not.

I have not tested the hard drive but the symptoms did not warranty that. Looking for opinions and possible solutions. Any ideas would be greatly apprciated. I am at my wits end!

Thank you for your time,

Jerry