The description of this problem is not an isolated incident - I have gone through 2 hard drives in two days. The first was already making loud noises, so I just went and got a new drive...
copied my back up over and it booted fine, put it in stanby overnight and when I was back in the next morning something happened to cause the VPU to require re-start (Screen went White, and HD continued to run) and finally I got it to go back to standby - then the system error stated that the VPU required restart, all rendering was now done by software and to re-initalize the VPU I had to reboot - so I did.
I have only gotten to the BlackScreen White Cursor since then.
I installed and ran the UBCD and it was able to boot fine (as was an old HD for a moment) - funny thing was I noticed that I could access the HD's (even the first one that I thought was physically bad) if they were either in the system or connected via USB - so the Drives were fine and data is in tact.
Still haven't been able to get beyond the BSWWC yet - going to complete the tests run above - but sure would like to nail what is causing this.
The other strange thing is that none of the HD's are recognized when connected to another PC. - but when connected to my laptop and booted with UBCD they show up and read-write find ? - I'll let you know how it goes.