Th7II Instability problems

I've run this board with 1.8A at 133FSB (1.75V) for the last week, now i'm getting instability issues e.g. suddenly the screen in Windows XP goes gray and i need to press control+alt+del so the whole GUI shows backup again. Also i get corruption of data in Wolfenstein i.e. my name changes in multiplayer to numbers, and sometimes it goes back to the main menu of the game for no reason.

I've put it back to default settings now i.e. 1.5V 100FSB, and i've still got the same issues!!!
I've used memtest and run it for 3 hours to check the memory, and its alright.
It does this in Wolfenstein in both of my hard drives, so i don't think its a hard drive issue.
Now the only thing i have left is a power supply problem, but i'm not sure if this would cause corruption of data??? Its an Aopen 300W psu: +5V - 4.92v 12V - 11.86v.
My voltage at 1.5V is 1.44V and it decreases by a further 0.4V under load.

What do you think is going on here?

My voltages are even lower but have to problems even oc to 2.4. My 12v bounces from 11.74-11.68 and vcore at 1.5 is 1.38. After a crash from unstable oc in rtcw it kept reseting everything to default on me but it was just the shortcut getting rid of the shortcut fixed it. Don't know how or why.anyhoo not that this blaber help you at all but I don't think its you voltages.

Your PS voltages appear to be the norm and probably isn't causing the problem. If your Vcore is reading 1.44V and drops .4V more then you may not be getting enough. Try increasing Vcore to 1.5V @ 1.8MHz and see if windows responds better. In my experience, windows seems to need the voltage to run smoothly.

If this doesn't work, then I would suspect that a PCI card (or the video card) didn't like running at higher speeds and finally gave out. Of course this is assuming you were running the bus's out of spec.

One other thought, you tried 2 different HD's--do both of them have there own operating system?

both of them are using one operating system - Windows XP which is installed on the SCSI hard disk.

This is wierd now i don't get any more errors @ 1.8 and i didn't change anything, now i'm @ 2.1 with no problems