black screen crash and sound loop

[electronic_matt]

I am wondering if someone can help me please, I have been trying to fix a friends PC for some time now, it crashes in games to a black screen with a buzzing sound looop, I have spent a lot of time looking online for answers and trying various things, it happens in games mainly, rarely in windows applications or desktop

motherboard is gigabyte GA-Z77X-UD5H, intel i7, 16Gb ram, 750w XFX PSU, samsung SSD, MSI AMD HD 7850 gfx card, can give more detailed spec

I have tried the following, updated bios, reinstalled windows 8 and 7, different hard drives, different gfx cards, cleaned the whole pc inside, reseated everything, checked all bios settings and voltages, unclocked gfx cards, tested with another PSU, changed gfx card slots, tested ram, I have done everything

today I noticed that the motherboard was not installed correctly (the system was not put together by myself) someone had used the wrong screws and I noticed a low buzzing kind of noise through the speakers, also tried headphones.

I decided to install the motherboard correctly, the buzzing stopped, obviously a bad earth. I have been testing with some games and so far no crashing, could this bad earthing of the motherboard cause that kind of crashing?

 

[Doogles]

I guess it could have been as I think you have ruled everything out except for a bad motherboard or CPU.

 

[electronic_matt]

It's does seem to have sorted it, weird really considering everything else i've tried and the time spent on it, fingers crossed that it was just the screws