Everything on my computer keeps crashing

[Hatix]

I built my first computer for gaming about a year ago and have upgraded it along the way. But now every time I open any program it crashes/closes almost instantly. I have tried many possible solutions on other forums and nothing works. I thought my ssd was going bad so i installed windows fresh on a hdd and still the same problem. I did overclock my cpu before but I put it back to stock as my gpu is not very good that it would help me much. I have tried updating drivers and doing all types of scans (anti-virus, advanced system care, malware bytes, ccleaner). The usual error that I get are "Access violation at address".

PC Specs
CPU: I5-2500k water cooled with Corsair h100i
GPU: Radeon HD7770
Motherboard: Asus p8p67 pro rev 3.1
8GB Ram 1600mhz i think
750 watt Psu
500gb hdd
128 gb ssd

Please help.

I just got an error, "The instruction at 0x779f24cb referenced memory at 0xffffffff. The memory could not be read. Click OK to terminate the program."
This popped up when i tried to open Steam.

 

[Hatix]

WHICH 750 watt psu?

I believe it is a Kentek 750w PSU

Update
I just looked up my motherboard manual and discovered that my ram was not supported by my motherboard could this cause the problem? I ran my pc fine for a few months before this

 

[SomeDude03]

Everything on my computer has also started crashing (all my steam games and google chrome) It used to not do this and i also tried a new install of windows but that didnt work either.