Hard drive problems..

So about a week ago I installed new a 1gig stick of RAM into my macbook. Everything worked fine for a few hours, then suddenly my apps didn't work and I had force a shutdown. After all that, my poor macbook didn't want to boot up.. Just got the blue screen and the question mark folder. I tried replacing the old RAM, but that didn't work at all. Apple ended up replacing the HD for free even though my warranty is up. So now I'm worried the same thing will happen if I install the new RAM again...

My question is: could the new RAM [it was from OWC] have caused my hard drive to fail on me? Should I even try using it again or demand a new stick from OWC?

Thanks!!