I've had my Macbook (10.5.8) for over two years and have had no problems until recently. It's crashed twice in the past month, and before that (for a few months) it has been extremely slow. I've cleaned out everything I didn't need and placed most of my documents onto a external hard drive in hopes that this would speed things up - it has not. When the thing crashes it basically reboots itself with out any warning, losing my data. Both times this has happened I had photoshop and Acrobat 6.0 Professional open (I've been editing photos of texts of my research and turning them into pdf - some of these files are quite large (400 colored pages) ie. 600mb). The system usually crashes and reboots while I am editing an unsaved pdf in Acrobat. Has anyone had similar problems? Any advice? Thanks!