I have a 13 inch unibody MacBook. I believe it's late 2008. I bought it last Christmas refurbished from Apple.com. I noticed a couple nights ago that it locked up and froze and the only way to get it out of that state is to force restart. That process takes up to 10 minutes. It usually started up in about 60 seconds. I reset the PRAM and did that repair disk permissions thing and nothing is helping. I was going to do a clean install of Mac OS X, but it started happening suddenly, so that's why I'm thinking it's hardware related. I made a Genius appointment for today at 7:15 pm. What can I expect them to do? It's still under basic warranty (I didn't get AppleCare). If something needs replacing, will they do it in the store? I've never had to do this before. Thanks.