Fans running fast, single long beep, no display or boot

Kekeb98

Commendable
Jun 7, 2016
1
0
1,510
I left my computer on overnight and in the morning, it was shut down. I tried booting it up and all the fans started working very fast. I got one long beep instead of the usual short one, but i got no display on the monitor (pc didn't boot up) and the fans just kept running very fast. I have a gigabyte motherboard, 12gb ram, ati radeon 5870hd 2gb..
I know the motherboard isn't dead because it still beeps if i don't insert the ram sticks correctly.
How do i boot up my pc?