WinDBG Virtual PC

I used WinDBG for debugging my drivers. Now I'm working on file system driver and want to save myself from OS reinstallations. So I thought running file system filter driver would be easy on MS Virtual PC. I installed Win XP SP1 on Virtual PC 2004, changed boot.ini to enable debug mode and if I select it, then my CPU goes to 100% and Virtual PC halts for a very long time. Hyperterminal works with the same settings as in boot.ini. Does any one ever tried it, or it would be easier to make HD image?