you power supply unit doesn't even have to be dusty.
There is a lot of cr*p out there, and I have a lot of horror stories in my library about weak power supplies (I got through 4 so far).
The only thing you can do: get an expensive, well known brand like enermax.
Te computer suck a lot of power while booting and maybe your psu is not able to keep up the voltages or the amperes needed - both ends in quiet interessting crahes - if the box boots at all.
but then wouldnt the computer not have booted at all from ther day he got it? it worked fine, and i mean perfectly fine, up until about two weeks ago when this memory error started popping up. Just so you guys know, i said i did everything i could think off, i meant everything, and this includes complete disassembly and cleaning. it was dirty, now its shiny, and it still doesnt work. as for a specific problem related to the model and maker of motherboard... its an ASrock. need i say more?