Since most of the threads seem to be complaints and problems, I just wanted to post that I had no trouble upgrading to Parallels 4.0. Just in case people read the forums and get scared away thinking everyone has problems with it. My HD crashed so in the process I decided to upgrade. Was a bit of a struggle finding version 3 which is required for the upgrade. The whole install went perfect. Only glitch was that after running a bunch of XP updates, I got some permissions errors. I simply reinstalled prallel tools and all was fine again.