Okay so I have a 24 inch 2007 iMac (the one with the iPad 1 looking screen with the silver around it) and I have been reading about some people upgrading their macs. First of all, how possible is it to do this? Can only a few components be upgraded? Also, I dont care about warranty since mine is not covered anymore. So I would not mind opening it up (obviously I would need to) Any feedback is appreciated. Thanks!