motherboard powers up but pc won't

Hi my desktop stopped working after moving into college.
I have an Asus A7V333 mobo and it has a green LED and that powers up when I plug in the power. But when hit the power button the PS fans don't spin and nothing powers up. I checked for loose power switch connections, loose cards/cpu, what could the problem be? I know last time I turned it off it was having problems keeping an accurate time. Maybe a dead battery. Any advice would be much appreciated.

Changint the CMOS battery is quick and easy, so you can always give that a try w/o much effort. However, I think your time clock problem and your current problem are probably unrelated.

If the hard drives don't spin up, replace the power supply. It is possible for the power supply to pass-through enough power for that LED light to come on, but still be faulty enough to not come on correctly.

I agree with jharnois. If a new PSU doesn't do it, then it's likely the motherboard itself.

Check the switch, too, make sure it isn't faulty. Do this by shorting the two pins together that the switch is plugged into on the motherboard. Take care not to short any other pins when doing so.

Can test the PSU seperately by shorting the ATX poweron pins to make sure not PSU, risky however if you are all thumbs with electronics. Plenty of instructions on net for doing it, and can test that the PSU is capable of powering up and not internal to it. This test does not work with all PSU, as a PSU may refuse to power up if no actual load on it. If you are getting green light I doubt however is the PSU but is easier to do then what follows, because you don't even have to remove the PSU from case to do the test.

A short on the motherboard will cause what you got and mentioned moving PC. By any chance you hear a loose screw or something rattle. It gets underneath the board and will cause short and board refuse to power on. And while board out make sure no small stands of wire on board, in card slot, memory slot, or accross pins of a chip (sometimes under a chip). Can get can of air and blow hell out of board including sideways to blow under surface mounted chips.

P.S.
When/if board out look over the capacitors to see if any are noticably dead or dying. Also plenty of instructions on web for how to look over motherboard capacitors. There are also MOSFETs to look at for noticable heat damage (also instructions on net for that). The capacitors and MOSFETs are common problems when it comes to dead or dying motherboards.

We're also assuming you've checked the power button's connection to the motherboard

For sure, check the switch by shorting (briefly, not leave short) the poweron (poweron of motherboard first, less risky that screwing with shorting ATX connection) and disconnect the reset switch from motherboard. And also if not already done try another AC wall outlet as the PC has been moved. Even if it powers a light bulb, as a PC is not a light bulb and far more selective. Wall outlet be one of the very very first things to check.

Never go the furthest when you may only have to go the shortest most easiest route. I would say things like pull motherboard and look over as last resort (especially if not traversed in pulling PCs apart).

i have the exact same problem, same green led on, with no power anyehere else, i even took out the psu, shorted th green and black wirs in the mobo power line, and the psu doesnt even work then, so seeing this im assuming its a psu problem and wil get it replaced as soon as possible.

maybe that fixes it.

I have the same problem also. I did put in a new power supply. It worked fine for about two weeks then did it again. Used power supply tester on first power supply showed good. Second showed bad. Put first power supply back in still would not work. Green light on motherboard nothing else powers up.