It could definitely be ram. I had the same issue, random files missing etc.
Run a memory test, like memtest86. Let it run a good 24hrs. If you don't want to try that, try running 1 stick of RAM or another type of ram.
Run a memory test, like memtest86. Let it run a good 24hrs. If you don't want to try that, try running 1 stick of RAM or another type of ram.