Locking up

My PC keeps locking up.
We have wiped it and re installed WindowsXP but it still keeps locking up.
If this is a hardware problem,does anyone know how to tie it down to which piece of hardware is causing this?
We have wiped it and re installed WindowsXP but it still keeps locking up.
If this is a hardware problem,does anyone know how to tie it down to which piece of hardware is causing this?