I was curious as to what the issue was that caused the failure. I decided to log the F12 diagnostics test. As each test started I recorded the name. As luck would have it I turned my back for a couple of minutes and the laptop did its usual thing by just stopping. I started the tests again and this time I had the laptop next to me while I kept myself occupied with a game on my desktop. When it reach the last recorded test I watched more closely and the last test before it crashed was XMATS32 of course this made no sense to me so I did a Google search and much to my amazement I found the answer.
There are 2 possibilities the memory sticks are bad (at least one) or the memory controller failed. One of the solutions was to run each memory stick through the test by itself. This meant 4 passes of the F12 tests. BTW the error was in the video memory section!
I decided to call Dell and reported the issue to 'call taker'. When I identified the test that failed and my disappointment with Dell support he reviewed the case, checked with his manager and, informed me that he was shipping a mother board and heat sync. In addition they were sending a technician to install the parts. The parts were to be installed on 2/15 but due to a prior commitment I rescheduled to 2/18.
When the parts were installed I ran the F12 Diagnostics (BTW the XMZTS32 is the last Diagnostic, go figure). For the first time the F12 completed with no issues. I immediately reinstalled Windows 7 and currently installing support software. I am not that technically astute and I cannot why they will not support Win 7 but like I wrote 7 has run for the last 4+ years without incident..
I am totally frustrated with Dell support. I took a month to resolve an issue. Of course they refused to listen tom me and perform the necessary test to isolate the problem, just lazy I guess.
Sorry for the long rant but I had to document this 'lack of support' which I paid for. Sad