Thank you for the reply (and for moving my topic here, sorry for posting it where it didn't belong). Unfortunately, my problem happens on a laptop, so I don't have a CPU to test and, even if I did, I have no idea how to do that, hahaha. In fact, I don't know how to do most of the things described, unfortunately. I only use the computer and my knowledge of its inner parts (either software or hardware) is fairly limited. :S
I have entered Safe Mode, though, and, so far, nothing's happened. In fact, when the laptop would freeze as soon as I turn it on, I would turn it off through the button, turn it on again after a little while and enter Safe Mode. From there, I reboot and, usually, Windows is able to load normally. But, these past few days, the laptop has gotten frozen not on startup, but while doing other things, like being away-from-keyboard in a videogame. Also, I noticed it's rebooted itself spontaneously, a couple of times, even though I have deactivated the "automatic reboot" thingie that supposedly makes a computer reboot when getting a BSOD.
I have no idea how to access the BIOS to check the things you suggested, but I'll look and see what I can find... Maybe something will turn up. :S
Thanks for your time and suggestions.
EDIT @ 2013.02.01: I just managed to get a picture of the freezing + weird lines in the screen. Maybe this will shed some light into this awful matter... >.<
Edited by Hiyoko Tachikawa, 01 February 2013 - 11:48 AM.