Just now I came home, and went downstairs to work on my development box.
I noticed that the power LED had gone yellow, like it was in standby, but when I jiggled the mouse nothing happened.
I figured it had crashed and attempted to do a hard reset with the power button, but that was unresponsive. After that didn't work, I unplugged it, then plugged it back in and tried to start it up with the power button, but that didn't work.
I then checked all the connections to the motherboard, but they were all tight and contacting. So then I checked the PSU; and for some reason, after turning the power selector switch (115-250 VAC) to 250 and back to 115, it worked... somewhat.
Currently, when attempting to start it, all normal LEDs will come on and the fans will start, but there is no output to the monitor at all, and the motherboard does not beep. Also, it takes an unusually long amount of time to respond to the power button.
My current suspicions are either a bad MoBo or a corrupted BIOS, but is there a way to tell for sure what is causing the problem?
I have had no problems recently before this.
HP Pavilion S3000y (original PSU, motherboard, and HDD)
Intel Core 2 Duo 1.87GHz (original)
XFX Radeon HD 6570 1GB
2GB RAM (original)