OK, nihil, you can bash me now for reco'ing chkdsk.
I have nothing against chkdsk. I am just cautious as to when I use it rather than a manufacturer's diagnostic toolset.

Basically, chkdsk is intended to fix Windows file problems. If you suspect that you have a physical hardware problem then chkdsk can do more harm than good and won't provide a long term solution.

In fact I have just run it on this machine....................but I didn't believe that anything I or my hardware did took out half the town's power supply for twenty minutes