After being away from my home and my computer for about a week and a half, I came back yesterday and tried to turn my computer on. The lights for the computer case turn on, the fans turn on, but nothing else seems to work. The monitor, even though it is on, stays blank with the orange standby light, as if the computer were still off. I don't hear any beep codes, even though the speakers are on (the blue light on one of the speakers is on). The keyboard's lights don't come on and the CD/DVD drive won't open either. Everything is securely plugged in as far as I can tell (I even opened up the case and everything inside it seems to be plugged in), and the power cables are plugged into a surge suppressor power box, or whatever it's called.

I searched online and found that unplugging the power cable and holding the power button for a minute could help reset any electricity in the components and could possible help. I also found that taking out the RAM modules and putting them back in might help. Neither of those worked, though.

Any ideas?

Note: I previously posted this here, and I have already tried a few new ideas. These quotes summarize what else I've tried:

If you have more than one RAM module, one or more might be bad.

If your optical drive won't eject the tray then your PSU has been battered with flour and deep fried.

I was about to reply asking if the PSUs I picked out were good for my computer's specifications, but while I was typing this post, I decided to mess around with the cables some more. Most of the power supply cables in the case seemed to be pretty stuck, but I was able to take out the one going to the optical drive and then put it back in. Somehow, after I turned the computer on, the optical drive could open and close again (the monitor still doesn't show anything, though, by the way).

You wouldn't happen to have a spare computer/parts around would you? I'd start off by checking:

RAM
Video card
Motherboard

In that order.

I second Ultimate Dev'r debugging advise; at first glance it sounds like it might be the PSU, though.

It is easy to test. Simply jump the PSU (short the green and black wires on the 24 pin cable) and let it run continuously for 24 hours or so, see what happens. Just make sure you've unplugged the PSU from the motherboard and video card. I'd leave everything else plugged in so that there is some load on the PSU.

Or so I've heard, anyway. Don't take my word for it.

That advice sounds eerily familiar

I learned from the greatest.