What can i say ?
WINDOWS XP SUX ?
Try a DIR from the commandline, as TH300 sugguests, to see if there are any files. It may be that windows f*cked up moving the files.
The way windows moves stuff is by 2 commands: COPY and DEL, so check your wastebin to see if there's anything in there. Also, have you tried an undo ? (this won't do you any good if you've already rebooted the system after you moved the files, since the undo buffer is then cleared).
Other then that: good luck !
As a note, i should add:
I rarely use move. If i have sensitive stuff to move (even in win 98SE), i use copy: then check if it copied, THEN delete the old copies (or keep them, if they don't bother me).