Help. All my fans have stopped working except the PSU fan.

Help! All my fans have stopped working except the PSU fan.

Hi there. This year I was building a new system with the help of some of the good folks in the building subforum. My system has been working fine til just recently. The computer shut down twice yesterday for no apparent reason. I tried some things to resolve, like the Power button (30 seconds) thing, cleaned things up on my system, and it was working fine again for a few hours.

I got home from work today .. and it won't boot. So I took it off my desk, unplugged, moved to another desk, opened it up, plugged the power in, and watched what was happening. The CPU fan, back fan, and the front fan are refusing to spin (they don't start at all), but the PSU fan does. The two graphic card fans won't spin either.

My computer is clean. All the components are less than a year old, so there's no reason for any of them to be failing. I was going to take it apart and plug everything back in to see if it works, but I wanted to leave this here to see if anyone has a better idea. How could this happen out of nowhere? All the fans were spinning last night, and I was playing MGSV Phantom Pain with temps between 50-65 (depending on where I was) so I don't have temperature issues. I also had a graphics card crash last night on a really old game despite my card being bought this year. The graphics card still has the power light when I plug the mains in. Appreciate any help with this random issue :sad:

(Also, I have no spare PSU's to troubleshoot whether it's a PSU fault.)

Specs
Motherboard: Gigabyte H81M-DS2V
Processor: Intel i5 4590 3.3Ghz
Memory: DDR3 8GB
Power: 350W Corsair PSU
Graphics: Geforce GTX 750 Ti 2GB
Case: Cooler Master N200 Mid Tower Micro-ATX Chassis (Black)
OS: Windows 7 64 bit Home Premium