My computer just shut off on me while I was watching tv when I try to turn it back on case PSU and CPU fans spin GPU does not, put in an old 7900 fan spins on that but still not BIOS or anything on my monitor. tried shorting CMOS and attempting the onboard GPU still no Bios. I'm wondering is this my Motherboard? I am freaking out I only have 150$ so if I can't fix this I am boned, and I hope some one can help me fix this.
Do you have a case speaker? The beep codes they give off can be a huge help in diagnosing problems, and if you don't have one you can get one pretty cheap. I've seen similar behavior to what you're describing and figured out I had a dead motherboard. I even got a power error from my speaker but tested the voltage from my psu and it checked out fine. If it appears your psu is working fine then there is a very good chance you have a dead motherboard.