Less strain on the motherboard or power supply or whatever.
There's another showstopper, bad memory:
http://www.memtest86.com
With that out of the way, what are the brand/models of the harddisks used, where did they come from and have they been tested with the manufacturer utility?
I find it very odd windows downright crashes during the install when using a different harddisk, not something I'd suspect the bios for.