First-off: I'm fairly amateur at repairing hardware components of computers, but I know most of the basics.
The Problem: When I turn on my computer, it turns on but the monitor goes immediately into Power Saver Mode (the usually green light on the monitor turns orange). I know this is not a monitor problem because I tried another monitor on my computer and had the same result. I also tried reseating the RAM, replacing the video card, and taking out the motherboard battery - all to no avail. All the fans are working, some were quite dusty so I cleaned them, but got the same result. There was usually a system beep during the boot, which is gone now. But does this mean that the Power On Self Test is failing or that it doesn't even get to perform the POST? I hit the keys on the keyboard (which normally brings it out of Power Saver Mode during every day use) and nothing happens (the caps lock / num lock light seems to react within the first few seconds of boot, but after that no luck). Moving the mouse doesn't work.
Any help on this would be greatly appreciated. I've been trying to solve this problem for a while now and would prefer not to go out and buy a brand new PC.