My mac has been acting up lately. Apps closing unexpectedly, thing freezing frequently, on occasion trouble starting up, ext. (I still have nearly 30 gigs of hardrive space available.) My mac is about 6 months old, and I'm quite new the the mac world, so I'm just learning how to understand the behind the scenes aspect of the computer. Are there any ways of going about trying to quicken up my mac, or anything at all that might help it's performance? thanks for any help.