I have a desktop computer that won't turn on. I push the power button but nothing happens.. It worked one day and the next day I went to turn it on and ntohing happened...

What are something's I can do to see if I can get it working? I don't really know much about computer's so I have no idea where to start..

This might not be it, but that happened to my grandparents once, and it was because it was dusty, and was over heating there for it wouldn't turn on.

Other then that I really don't know much. Sorry.
Hope that could help a little.

Check power - wall outlet, power strip (dog step on switch?), recent thunderstorm, cord fell out of socket on back of computer, etc. If there is power available, but the computer doesn't even hiccup (fans turn for a second) when the power button is pushed, then the power supply or motherboard could have an issue or more rarely the switch itself. The wiring from the switch to the motherboard should also be inspected for proper connection. If it does hiccup and then shuts off again, both power supply or motherboard could still be the culprit, but more often it is a issue with memory or another component. Depowering the board by removing the cord and removing and reinstalling the memory modules sometimes corrects this situation.