I think I have again decided to buy an iMac since I dont want to wait until next Spring/Summer to get a new computer. My question is: what can I do to make sure nothing is wrong with it? Someone suggested a hardware test. How do I do that and is there anything else I should do? Also, if there is something wrong, how long will it be until the problem emerges? Right away, after leaving it on all day, or after a couple weeks? Finally, if it does have a problem, can I just take it into the Apple Store 15 minutes away? Will they fix it for free?