I've been getting a lot of lockups lately. Generally around 2-3 a day. I generally don't have too many tabs up, and am running Firefox + Adium and maybe iTunes. What usually happens, or at least the start of it is that the computer starts freezing at random, and then unfreezes. Often Apple + Tab won't shift through programs, and Expose won't work. I generally can't restart my computer through the Apple Button (that disappears sometimes) and have to do a Hard Shut down. Any ideas? I'm thinking of bringing it to the Apple Store, but I literally have to use this computer every day for things, it's hard to let it go, even if it's for a day or two. I'm on a Penryn Macbook Pro that I got in March or so.