Large File Copy Freeze, Hardware Setup

"Have you run any stability checkers on this machine? You need to rule out ram / cpu / high load which results in breakdowns, I would also run a HDD stresser / checker. That way you should be able to 'crash' your machine by your terms, and replicate the issue.

I would recommend something like:

memtest 86 - for memory checking
Prime 95 - for stressing / loading the CPU
HD Tune - for benchmarking / stressing the hdd's

After you run those, you should get a better idea of what the cause is. So until you can safely replicate the hdd issue as the hard cause of your crashes, I would say run the tests."