Harmy said:
So the computer is up and running but I don't have legally activated Windows yet, because I ordered it slightly cheaper from a different company and it hasn't arrived yet - but hopefully it should arrive today or tomorrow at the latest. Meanwhile, now would be ideal time to test the HDDs but I really don't know how to go about it.
Check this article out bro. It may help you out.
http://pcsupport.about.com/od/toolsofthetrade/tp/tophddiag.htm