Question : Problem: N351S1 Unable to Boot, Random Bluescreens

My Uniwill N351S1 laptop (P4 3.06Ghz desktop CPU, 1 GB RAM, GeForce 4 Go 64MB, Windows XP Pro Corporate) recently started refusing to boot up.  Usually it will show the power lights for a second or two then shut itself down totally, after the fan starts up for a split second.  Occasionally it will boot up, only to see a bluescreen of death a few seconds later (the error in the BSOD changes, the most recent was STOP 0x0000007F).  I had it working in Safe Mode (with Networking) this morning for a while, I used it to backup most of my important documents to the network.

Another odd thing is that occasionally when it does display anything on the screen at boot, it will clock the CPU back to 2.30 Ghz (my CPU is rated and configured at 3.06 Ghz).  It seems to do this randomly, or after a failed boot (occasionally it will keep the power lights on, not shutting down entirely, but will not display anything on the LCD) which might indicate a power or CPU problem to me.

Things I have tried:
- Reseating the CPU (and replacing the thermal pad with Arctic Silver 5 thermal compound)
- Reseating the memory (1 GB [2x512MB], I don't have any compatible SODIMMs to try replacing it with unfortunately)
- Booting without the HDD
- Booting without the DVD combo slimdrive (got me into Safe Mode for a while, but still bluescreens in Normal Mode)
- Taking apart the entire laptop down to the motherboard (I didn't go as far as taking it out) and putting it back together per the service manual

A laptop repair shop here in London, Ontario said that it's probably a system board issue and would need to be repaired / replaced by the manufacturer, but looking at Uniwill's policies, that could become very expensive very fast.  As mentioned previously, the retailer I bought this laptop from, Internetishop, is now out of business, though I would have been out of warranty at this point anyway.  I'm also worried about their "we will reformat your HDD if we think it's necessary" policy because, having done phone technical support for HP and Compaq, I've seen some customers burned by that in the past, and I have a bunch of data on that HDD I wouldn't want to lose.

I'll probably call Uniwill about this pretty soon because I can't afford to be without this laptop for much longer.  However, I would appreciate any assistance given here.  I am an A+ and Network+ certified technician but I believe this has gone beyond my capabilities.  Suggestions?  Also, could someone suggest a decent hardware diagnostic software I could use to determine if indeed there is a piece of hardware in the laptop that is faulty?

Answer : Problem: N351S1 Unable to Boot, Random Bluescreens

This could be a memory problem. Test the PC using memtest86 from http://memtest.org or download the UBCD which has other memory testers as well, plus othe tools you could use to diagnose your PC.

http://ultimatebootcd.com

Remove one of the ram sticks and test your PC just with one at a time. Test it in both slots. and give memtest at least 5 passes if no errors are immediately found.