OS XP Home
512mb RAM
ASRock 775i65GV Mobo (onbard graphics only)

The PC from first/cold boot shows CPU usage at 100% using Task Manager. Sysinternals Process Explorer shows that this is being caused by Hardware Interupts. If the PC is then restarted it mostly runs normaly.

Have tried swapping out RAM, disconnecting floppy and CD/DVD drives as well as removing all internal cards etc. Have only keyboard mouse and monitor connected. PSU seems to be putting out correct voltages. Have also tried replacing the HDD and ribbon cable.

Has anyone any ideas as about the only thing left to try is replacing the Mobo

Hope I have given adequate details.

Any and all suggestions gratefully received.

TP