Is it safe to delete Windows post installation files?
I have Windows XP installed on the first partition and the second partition is empty. I also have an external hard drive plugged in. I installed Windows Vista on the second partition and now my external hard drive got some odd files that I don't have permission to access. What are those files and is it safe to delete them?
Yes, it is safe to delete them. Sometimes you need to take ownership (and then change permissions) before trying to delete them.
Take ownership is explained here: http://www.vistax64.com/tutorials/67717-take-ownership-file.html