Random Crash & Nothing Will Fix

Today I was using my computer like normal, playing a game of Left 4 Dead 2 when all of a sudden the whole computer completely locked up. I turned it off and turned it back on not thinking much of it but when I tried to boot Windows 7 it would say Windows Starting with the logo, but then just restart.

I figured that perhaps my hard drive had died, but I later found that I could boot in Safe Mode just fine. I have tried Startup Recovery which said it couldn't fix the problem, I have run System restore which only gives me a very limited date range, and that often says it couldn't restore the system. I ran chkdsk as well and nothing has helped. Since it works in Safe Mode I figured that it may be a program that may be causing the problem when it boots so set MSCONFIG so that only the basics should load on startup yet nothing changed!

I have no Windows 7 CD because I got it at a very low-price through Microsoft for being a student. They gave me a digital download but I had also checked the option for having a disk mailed to me but they never ended up sending it! So I cannot use my disk to try and repair my operating system.

Anyone have any idea as to what the heck is wrong with my computer and what I could possibly do?

Hmm, I tried doing the clean startup but somehow that still didn't work. Something to be noted is that every time I would disable all non-Microsoft services and then click Apply, Norton 360 would automatically recheck itself. I uninstalled it once but I think the system restores I've attempted brought it back. I just don't understand what could make a safemode boot-up work but not a clean start-up.

Removed Norton but still no dice. I'm wondering if I should do another system restore now that Norton is gone? Or would it just bring Norton back?

What is the temperature situation?
Is it dusty?
How is the power supply?
What are your specs?