I have a Gateway all in one, about 3 years old with Windows 7. I use this computer for business and personal. Do some internet browsing, graphic work on photos, and drawings in CorelDraw. No games.
This has happened about 30 times, 2 or 3 times a month since Dec 2011:
BLUE SCREEN with message:
Call your hardware vendor for support
NMI arity Check / Memory Parity Error
***The system has been halted***
At one point after the first couple of BLUE SCREENs, I had a local computer guy take it in and he replaced the hard drive, $400. I took it back to him a couple of months ago and he couldn't find a problem ($45). He said the memory is okay. I never lose data after restarting, except whatever I'm working on and haven't saved or backed up.