Hi, after spending time on my computer, randomly it stops working. the cdrom and cdrw become inactive, the monitor cannot get a signal, and the only way out is switching off at the wall. ctrl-alt-del, and the restart button don't work. both lights stay on on the front of the computer. then the computer will not work again for another 45 mins without the same thing occurring.

could this be an overheating problem? power source? is there a cpu temp monitor out there i can download? HELP!