Uninstalling Issues....

I recently used Boot camp 3.1 to partion my HD for a Win7Ultimate x64 installation. I installed all successful and was using Win 7 from a 'option' boot at the Mac boot screen. I thought I would try Parallels 5 but it did not meet my needs so I used the uninstall process in the .dmg. All ok, I rebooted and pressed Option key the Mac now hangs on a white screen. I searched the help and ran the profiler uninstaller details but still I can no longer boot to Windows.

I have an iMac Core i5 running Lepoard 10.6.4.....can anybody help I don't really want to have to wipe the drive and start all over again and I dont even if know if that will fix the problem, especially as I use Steam and will have to reinstall all my games....

Please please help me ..... !!