My desktop tower won't turn on, but there's a green light at the back?

[nephtine]

Might just be some static build up so, like others have said, you need to power it down so, unplug it, leave it for a minute, make sure all cables connected properly (ie not loose), plug back in and power it on again. Static should have discharged by then and come back on. If it doesn't come back on, it might even be something as simple as the fuse has gone in the plug. Try plugging it into different sockets or try plugging something else into the same socket to check it's not a socket problem. If the socket's ok but the PC still doesn't power up, if you can, change the fuse. If you can't, it may be your power cable that's faulty. No need to give up the whole PC just for a faulty power cable. Find your manufacturer and model no and google for a replacement power cable.