Problem Caused by Update to New Build of Parallels 5

I upgraded to Parallels 5 in November from Parallels 4; this was painful and required complete reinstall of Windows XP and all applications. Only replacement of hard drive to eliminate parallels 4 install remnants allowed Parallels 5 to work properly. Installed Windows XP and related applications. All worked fine until I agreed to "update" of Parallels 5. Last week I did the update to the new build of Parallels 5. Windows XP will now not boot correctly. Windows starts goes to the blue and green "pasteur" screen, goes to loading personal preferences, and then goes to a blue screen with some error message that is flashed on for 1 second before rebooting. This sequence repeats for all attempts to start the Windows XP virtual machine. The error started immediately the "update" to the new build.

Please advise solution urgently.