I have installed my licensed Vista Pro four times on a clean virtual disk as a guest to Mac OS X 4.8 running Parallels Desktop for Mac 3120. Each time it boots once just fine, then on the second or third reboot, it freezes on the startup windows screen. I have been unable to reboot either to "the last working configuration" or far enough along to run "repair" from the Vista disk. It will boot to Safe without Networking, but there is nothing to correct, so the problem recurs on rebooting. Does anyone have suggestions?