PC won't boot after freezing

Hi, I have a gaming PC that I built about two years ago. I was playing Minecraft (CPU and memory intensive) and the computer froze and wouldn't respond to anything including ctrl + alt + del. Its never done this before so I held down the power button to turn it off but now it won't turn on again. When I press the power button nothing happens, but when I turn the power supply switch off and on and press the power button, the fans will spin and lights will come on for half a second then turn off. I thought maybe the CPU had overheated but after waiting a while it still didn't turn on. I also tried clearing the CMOS and cutting the power, neither changed anything. The motherboard standby light is on.

Any ideas? Thanks

My specs:
PSU:
FirePower ModXStream Pro 600W 80Plus Semi-Modular High Performance ATX PC Power Supply 600MXSP
SSD:
Intel 330 Series Maple Crest SSDSC2CT120A3K5 2.5" 120GB SATA III MLC Internal Solid State Drive (SSD)
Motherboard:
ASUS P8B75-V LGA 1155 Intel B75 SATA 6Gb/s USB 3.0 ATX Intel Motherboard
RAM:
Patriot Intel Extreme Master, Limited Edition 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model PVI38G160C9K
CPU:
Intel Core i3-3220 Ivy Bridge Dual-Core 3.3GHz LGA 1155 55W BX80637i33220 Desktop Processor Intel HD Graphics 2500
Video Card:
MSI R7770-PMD1GD5 Radeon HD 7770 GHz Edition 1GB 128-Bit GDDR5 PCI Express 3.0 x16 HDCP Ready Video Card
Windows 7 64 bit

 

I would try a different PSU first.
If you do not have a friend or spare PSU, and are very handy with a VOM you can check your voltage as you boot. I will not post how here as it can get you into trouble if you have never done any similar work.
Another check is to pull an much load as possible off the mother board. Use the onboard graphics, one stick of RAM, no HDD or anything else. See if the computer will get into the BIOS.

 

Thanks for the reply, I'll try what you said.