By RAM, I didn't mean the RAM itself is physically bad btw. I mean the timings might be too aggressive or the speed too high for the RAM. Although if you've run Memtest and everything is fine, then you can rule RAM out.

Lots of bad crashes can also corrupt your registry, but again that's not as likely.

Anyway if it keeps happening then look into it further. But if copying the file back works, then that should be a good enough solution.