"Hey, thanks very much for the comprehensive SATA cable review"

You're welcome! I didnt realise I could write so much about some cables...

Ah the 2500KS are the same as my WD.
Well SATA drives are cheaper now than the IDE counterparts but it wasnt always this way, as usual with emerging technology and pricing which gets more competitive as the market goes mainstream.

Have you dloaded and run the WD drive testing softwares? I am sure they must have such programs available. This might throw up some clue. Also have you enabled the SMART reporting on ur mobo?

Re your 6600 vga card, which version of nVidia drivers are you using? The drivers get optimised for the latest generations as they are released, you may find its better to purge the latest drivers and iinstall an older edition from a year or two back circa 6600 series hayday as it may well have better matched support.

Cheap PSUs can be temperamental. Saying that (touch wood) I have some cheapie EB 350w supplies that punch above their rating. I do like the Scan EZCool ones with the 120mm fans that help extract hot air from your case (450w/550w versions should be fine for you).
I wonder if you have someone there that can lend you another PSU thats higher rated or better quality so you can compare results and see if the problem persists.

Morg, if I am slow to respond here, feel free to PM me.