|These are difficult things to find. |
Basic choices are software, firmware and hardware.
You could try to reload the basic OS. Even use other OS's.
There are live cd's and other ways to run diag suites.
Many cases the motherboard has either suffered esd damage or had some mfg defect with parts.
"Best Practices", Event viewer, host file, perfmon, antivirus, anti-spyware, Live CD's, backups, are in my top 10