Win XP Pro won’t boot

We have a workstation that crashes upon booting every 3-4 months. This is time #3. The past 2 times have resulted in complete format and re-install of Win XP. The last time I replaced the HD. When I attempt to boot in safe mode, it lists the drivers, and stops responding there. Also, after the disk check completes, it just restarts and goes through the same. Any suggestions?
TIA