Yup, that'd be good - do you mean "backup server incase this new one dies?"
or "backup server to run backups and nothing else"?
i've got a couple of clients with pure backup servers...and that is the best thing..."need to restart...click"...no interfering with the office work
That stop error just indicates that you'll need to reinstall windows when you can...however you're having trouble doing that.
I'd suggest doing a memtest (
Memtest86.com - Memory Diagnostic) and seeing if the server has bad memory.