My bootcamp Windows XP crashed while I was in Coherence mode. When I rebooted it the task bar was missing in both coherence and windowed. I have read other posts on the subject and attempted the fixes. They have not worked. When I uninstalled Parallels Tools from XP, the task bar reappeared. After reinstalling Parallels tools, the taskbar again disappeared. I think its pretty clear Parallels is causing the problem, but I have not figured out how to recover from it yet.