Since upgrading to Lion my 2009 iMac has been going crazy. Glitchy graphics, random freezes, etc. I want to run hardware checks on it to make sure everything is ok but the only way i know to do this is to put my original install DVD in and boot up, etc. The problem i (might) have is that i'm on Lion, and my install DVD is Leopard. What i'm asking is.. will this cause any issues, or is everything fine seeing that i won't be using the disk to login to my OS?