My computer, in the last 3 weeks, has become increasingly moody. When I try to watch a video (on a secure, safe, legal site, such as watching a tv show on CWTV.com), or try to use my computer game, The Sims 3, my computer will start to run it and then show the "Blue Screen of Death" (where at the bottom it says its dumping physical memory to disc) before crashing and restarting. I have tried restoring my computer to a time before I was having these problems, but errors have occurred and the restore is never successful. I have disc DEFRAGMENTED my computer, and even turned of my Norton Anti-virus to see if perhaps it was MESSING with my system. I just can't seem to get my computer to run a video, tv show, or my computer games!!! I have also run a scan to see if Norton could FIND anything wrong with my computer! No luck!
I'm trying to avoid doing a faculty restore on my computer, and I have a GUT feeling that wouldn't help with this problem anyway.

My computer/system information:
Windows System Home Basic 2007, Service Pack 2
Dell Inspiron I1420
Intel (r) Core (TM)2 Duo CPU T5250 @ 1.50 GHz
2.50 GB
32-bit Operating System

Also, while it seems un-related, I've also had problems with my Microsoft Office Home and Student 2007. I reloaded it, and re-entered my product key only to find that Word claimed that "selection is locked" While I don't see how this could be related, I figured I'd mention this as well.

I'm completely stuck and very frustrated. It WOULD be GREATLY appreciated if anyone could help me figure out WHY my computer is acting up LIKE this! Occasionally the blue screen does not occur and the screen just goes black and restarts, or locks up forcing ME to restart the computer by pressing the power button.

Thanks for any help!