Computer wont boot

Hey about to weeks ago i was looking around on myspace and all the sudden my computer froze up. i waited a min then decided to reset my comp. I left while it was resetting and when i came home the computer was on but there was a blank screen. I thought maybe it was the screen saver but it wasnt. i then reset again and the computer remained on but nothing was shown on the screen. The fans worked, the harddrive came on, and so did the cd drive. I thought maybe it was a boot sector virus but when i took my hard drive to my other comp it worked fine and i went ahead and reinstalled windows to be safe. I then thought maybe it was my graphics card but that worked on my other computer as well. i have come to the conclusion that it is most likely my mobo or my ram. i will put my system specs up in a bit. I dont see what went wrong ive had the comp for 7 months worked like greased lightining lol now its dead. any ideas on what it could be would be appreciated.... i hope its the mobo i want a new one anyways lol

My first guess would be the mobo. Look on the board and see if you see any bulging/leaking/burst capacitors.

EDIT: It could also be a corrupted bios if you don't see anything wrong on the board.

ditto on the mobo if you're not even getting a post. reset the cmos via jumper with the battery out and power supply unplugged. also reseat memory, cpu. remove any pci cards, and try it with just graphics card, cpu, and ram and see if it posts. add other items if this fixes that problem as something might be dead.