I work at a restaurant and one of our computers was having all sorts of problems lately. The computer turned itself off after about 3-5 minutes. After that it wouldn't turn on again and when I tried to turn it on the power light / keyboard lights would blink but that would be it. About 2 hours later the computer did turn on but the monitor said "No Signal" (yes the monitor was connected).
I just put a grahpics card in and connected the monitor and it still says No Signal. Any suggestions / ideas?