Help me Diagnose this issue

Hello, new poster here. I'm currently having an issue with internal equipment that I'd like to get diagnosed. So let me see if I can post everything I know about it, and two images to actually what my screen shows.

For about 3 months now, my computer has been freezing up on and off. Sometimes when I'm playing a video game(WoW, TF2), or sometimes right after I login into my username on the PC.

Well, on Thursday of last week, it lasted about 45 minutes tops, and then it started giving me screen freeze, with all kinds of little lines through it so I shut it down, and then tried to restart it multiple times, only for it to freeze up and look like this in these images posted. Image links are here. one and two

Now I can't even get the machine to start. It sounds like it's booting up, but no screen is being shown. Any ideas as to what it could be? Thanks.

Reply 1 : Help me Diagnose this issue

While it sounds like heat, it could also be an overtaxed power supply. But your top entry post while good seems to be missing a few details.
Bob

Reply 2 : Help me Diagnose this issue

My powersupply is 600 Watts. It's custom Built from Tiger Direct, it's 2 years old, the fans as of two weeks ago were working, but it was still freezing, which prompted me to clean it out. I did that, and it ran fine for a week, then it randomly froze or wouldn't start.

Reply 3 : Help me Diagnose this issue

The images do like the usual overheated system and a failing video card but I can't tell which I'd pick given such slim details.

More details and more story such as how you clean the vents, heat sinks every 6 months.
Bob