I've had my computer for about 3 weeks now and nothing has gone wrong, but I got home tonight and it wont power on. No lights on the mobo, nothing. It was working fine 6 hours prior and I left and came back in that time so nothing was done to it. I tried plugging it into a different wall socket and flipping the power switch on and off and nothing is working. Please help this is my first computer that i've built and I have no idea where the problem might be.
What PSU are you using? Also, do you have any other parts you could switch out temporarily? Like take out the power supply, put in an old one and test to see if it will start up?
And have you double checked that all the cables are connected? Maybe one of them came unplugged somehow though I'm sure you've already checked.