|I'm basing this on the photos from Google:|
Assuming that's a "regular PC", I'd first suspect a broken connection somewhere between the monitor and the output port (VGA Card?) that drives it. If you're not getting any beeps, however (assuming that it's supposed to beep---some PC's don't), that could indicate something in the power-supply has failed.
I'd also suspect that the CMOS battery is long dead (you stated it's been sitting over a year). That would cause a wide array of problems, depending on the model of the PC.
"Channeling the spirit of jboy..."
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