So i've been having computer problems on and off for the past couple months. What happens is the display goes out and the computer freezes, whatever last microsecond of audio that was playing repeating over and over until I hard power off the computer. This has happened during games, while just browsing the forums, even sometimes immediately after Windows loads up. On top of this, sometimes when I power off the computer after this happens then power it on again, it won't POST. It just sits there, powered on, fans running, but with no beeps and no display. Shutting it down once more then powering it on again usually results in it finally booting.
I've run a memtest and it found no errors, but I have no idea if that means anything and I don't know what other diagnostics to try. I can't exactly afford to replace parts on a hunch or to see what works and what doesn't, i'd like to know what the problem is before picking up a replacement. Anyone have any ideas?
Most of my parts are a little over two years old, though I think the power supply is a bit older than that.
Intel Core i5-3570k Quad-Core 3.4GHz CPU
GIGABYTE GA-Z77-DS3H LGA 1155 Intel Motherboard
ASUS GTX650 Ti 1GB 128-Bit GDDR5 Video Card
4 x 4GB DDR3 SDRAM
Rosewill 550W ATX12V v2.01 Power Supply
1 x 2Tb HDD
2 x 1Tb HDD