NT:Repair, Reinstall, or??

A workstation on our network had a prob with keyboard dropping. Mouse worked, keyboard would drop out. After trying 2 other keyboards, symptom the same. Suspected motherboard, so…

Replaced & upgraded with new motherboard & CPU (faster CPU, different mobo), same NIC & Video card. Restarted the sytem, seemed fine. Now user reports system hangs intermittently.

What to do?

Use REPAIR, from NT floppies? Total reinstall of OS & Apps (fdisk upward?).

Any advise greatly appreciated!!!!

Randy L.