i was playing Garrys Mod, when my computer froze, so i turned it off, waiting a while, turned it back on and the moniter said NO INPUT SIGNAL, it is a 5-7 year old Alienware PC with a newer graphics card, (ATI RADEON x1600), and the power supply says the max to run on it is 520 watts, plus we have cats and other things in the house, and the room isnt very cool, so after can airing everything off, i plugged it back in and tried again, still a blank screen, any immediate help would be appreciated.

The only real way of determining hardware faults like that is to swap it with another graphics card if you can and see if that works. I used to have that graphics card and it died on me also, worst card I ever had.