Finder + Stuffit

I had a problem with Finder before Apple told me to wipe my MBP clean and start anew. It always relaunched itself when i was using Finder and navigating in at random times. So they told me to wipe it and try it again. I jsut finished doing it, and it's happening again. What i did notice however, was that it started happening before once i installed Stuffit Deluxe 11. Now i installed it again first thing, and it's happening again. Could the program have screwed it up in some way? Now Apple said if this happens again, it is a RAM problem. Which do you think it is?

Can't anyone help here?

Replacement

I have a feeling my 2nd MBP will need replacement, again, and i was wondering if when i get a new one, will it come with Leopard installed? Here's the problem i'm having with it: http://www.mac-forums.com/forums/showthread.php?t=82323.

Yes it will come with leopard installed.

If your notebook is replaced, then you will receive exactly what you received when you purchased it initially. Your notebook would be replaced with an exact same model as the one you bought.
In other words, you will not get a free upgrade to Leopard.