I have a Macbook Pro that's about two years and 4 months old, running the latest version of Leopard. I was problem free for about two years until last October when my MBP suddenly wouldn't boot up (hung at the grey apple screen). I took it to my University's computer repair center, and they said either there was a corrupt OS file, or my HDD was going bad. I went home and booted from my OSX disc and did a full erase and install. My computer worked fine for a few months following the erase and install, so I assumed the problem was alleviated. However, about two months ago, my MBP started freezing periodically. When it freezes, I get the spinning beach ball, and there is an audible rapid 'ticking' sound coming from what I can only assume is the hard drive. The only solution is a hard restart. It used to occur rarely, but seems to be getting more frequent, and it doesn't appear to be limited to periods of heavy memory usage. In fact, since I did my erase and install several months ago, I only put essential applications back on. Typically, the only things I have running are Mail, Safari, sometimes Word or Pages, and sometimes uTorrent. I have 2GB of ram and over 40GB of free space on my hard drive, so based on my usage and the running processes, I think I can rule out a lack of memory or hard drive space. This evening it was so bad, it froze while I was trying to reorganize my itunes library. I restarted and opened ONLY itunes, and was listening to music while renaming songs, and it froze again within 5 minutes. With the situation looking grim, after the next restart, I wanted to just open finder to copy some important files to my external HDD. I opened my external HD folder and when I attempted to open my 'Downloads' stack, it froze once again. I gave up for the night and will try again tomorrow. I have tried all of the disk utility tools, and none have seemed to make a difference, or report a problem. Does this sound like a software or hardware problem? Sorry for the long post, but I wanted to be as detailed as possible. I would like some thoughts or suggestions before I make a trip to the apple store.