wow thats crazy! in a hotel room. Did you report it? He didn't intentionally leave a trail. This is left over during the uninstall and he probably thought he installed it and got stuff and then uninstalled it without a trace.
Or he might have tried to load up Windows 7 afterwards and went "Oh Crap what do I do now...."
See here for info: How to uninstall Linux
Check out the section on Super Grub Disk and Ultimate Boot CD you should be able to get rid of grub from there. and then run the install CD. That "should" work....