Toshiba Satellite L555 freezing up! (Tech Head Challenge) Please Help!

Question

It's been happening lately. My Toshiba Satellite(windows 7 home permium 64 bits) has been freezing up with multiple, thin, multi-colored lines with a noise similar to when a sound track on a CD sticks or freezes and no mouse response or any kind of response at all. I have to press and hold the power botton and force it to shut down. I noticed it does this more often when I try to play a video game,virus scan,video call on Skype and less frequently on youtube (youtube might just be a coincidence). Sometimes after the computer restarts and I virus scan or Skype then I have no problems. I think it happens when I virus scan or skype when I have both multiple firefox and google chrome windows open at once but I cannot be sure. I've tested the theory a few times but it's inconclusive however I am confident that virus scans or video game are most likely to trigger the freeze even if they are the only thing I have open on the screen.
Sometimes I get that message in the blue box that says "Windows is shutting down to prevent damage to your computer....." The strange thing is that after I force it to shut down if I try to restart it immidiately then it will boot. All the lights will come on except the orange one in the left hand corner,the screen does not come on and windows does not load. If I leave it for 30  minutes or sometimes less after it crashed then it will restart .The funny thing is that I had this problems about 8 months ago when I tried playing a video game called A.V.A. About 2 minutes into play it would freeze with the same noise I mentioned earlier.I repeatedly tried to play the game and it happened every single time and everytime I force shut down the laptop and try to restart it right after then windows will not load and the orange light does not come on. I removed the game and reinstalled it and I never had that problem again.Since I got the laptop it has randomly restarted like 4 times and I've had it for about 1 year and 2 months but now it is just freezing up (mostly) or I get that message in the blue box. At around April of this year the game stopped working. I keep getting error reports when I try to reinstall it and my windows no longer recongnized the digital signature of the company that made the game.
I'm not sure if it's overheating,I have a hard drive or motherboard problem or if it's a software problem. I've tried:
System Restore
Defrag
Disc Clean up
Non of these have helped. I've also tried using SeaTool for Windows to try to look for errors in my hard drive and it has not found any. I've also done that thing where Windows,with the black screen and white text, check through your files for errors and corrupted stuff but that report says that it hasn't found any errors at all. My computer has no slow down in performance that I can notice. It doesn't take long to start up nor does it take long to shut down. I don't get random error reports or anything like that. It works fine except for the freezing bit.
The fan seems to be working just fine and the latop doesn't get that hot. Sometimes it freezes when it's barely warm to the touch and other times it would be significantly warmer but it would not freeze even if I have multiple firefox and googlechrome windows open. Before all of this when my game was working I use to play for hours with the exhaust at the side significantly heating up the desk and the computer would run perfectly without problems except that brief period I mentioned earlier where the game froze 3 minutes in to actually playing the game,reinstalled it and solved the problem. Yesterday it froze on me while I was on skpye and today it froze on me about 5 minutes after windows log in on youtube without the computer getting hot,just barely warm. I just don't get it!
I've try using a vaccum to clean the vents without opening the computer. I've removed and reinserted my memory just incase they were loose and I've also removed and reinserted the hard drive to be sure that it was in properly and that has not stopped the problem either.
N.B. I did do a virus scan with a trial version of Kaspersky Pure that I installed less than a month ago and it does say that I have a virus called "virus heur trojan.script.iframer" and a medium and high risk events. I've tried to remove or quarantine them but nothing happens and when I scan again with Kaspersky Pure or Kaspersky Virus removal tool they find no viruses BUT the trojan report is still there with the option of removing and quanrantine.
As I've said before I've seen no slow down in performance and it works just fine except for the freezing and the blue box message. The only noticeable problem is that both firefox and googlechrome have been just a little,little bit buggy in that sometimes I would have to close down a window and reopen it again because the pages were not loading but that's only on Facebook and a few other websites and I thnk that's because of my internet connection. As I said, I've gotten no random error reports,not from windows 7 or my browser.
Please help!

Answer 1

It sounds sort of like it could be related to overheating, but on the other hand, you specifically said that it doesn't always feel warm. If you're okay with backing up your files, you might want to perform a full recovery back to factory default conditions. At that point, you'd at least know whether it was due to hardware or software.
- Peter