My MacBook gets slower and slower and I try to nail down the problem. I have now reinstalled Mac OSx and already trashed shapeshifter, Office 2004 and other certain things I don't REALLY need .. Last thing to try out / remove / keep : Parallels. One question : I know the first thought / answer is probably "of course not" but I dare to ask anyway: Did you even experience that you MacBook is performing slower after installing Parallels ? I mean slower without running a virtual machine in the background, just the installation (due to virtual NICs or whatever reason) ? This is the last thing I can imagine ...