Just finished installing the latest version of Parallels (3.0 build 5582) in my MacBook and everything went well except that when I try to use it the Window remains black and nothing happens with the following message: 640 KB Base Memory 524288 KB Extended Memory Boot from hard drive... - I tried deinstalling and reinstalling Parallels several time but did not work PLEASE HELP!!
I actually was able to fix the problem by creating a new virtual machine (File/new) and reinstalling Windows XP. Then I deleted the old virtual machine, which occupied 800 MB memory from a folder called Parallels, that was located in my Documents Folder. I hope that this helps someone.