Computer turned off and won't turn back on
Hey guys, so I was just watching a video on youtube when suddenly my computer turns off, in fact everything being supplied by the power through the sockets in my house turns off, so I go to the main switch thing and flip the switch, power returns (wooh!), everything works except my computer. The monitor turns on and off though. I thought that the psu was the problem but I checked that and it works fine, when I look at the motherboard while the plug is on I can see a blinking green light on it (don't know if this mean anything).
To conclude my PC isn't working, my PSU is working and a blinking green light is present on the motherboard, any help will be appreciated thanks!!