Hi. LV crashes even you don't open any vi but LV menu only? I experienced some bugs before with certain vis in LV. While open and running they didn't report any error, until LV closes. The problem were some bugs which if executed, they overwrite (or try to overwrite) memory out of LV space, when LV closes, LV detects this memory corruption and reports the error. Each version of windows have more error detection than previous versions, means it would have been a but never detected before, but detected only by the latest version of Vista.
Good Luck.