Just from the data you've shown us, which looks like it is Base64 encoded, nobody could tell for sure what encryption was used here. MD5 is
not an encryption method, it's rather an algorithm to generate a hashcode. This is irreversible so once the hash has been calculated it is impossible to generate the data from it.
Here is a page with a couple of links on it regarding encryption:
http://support.microsoft.com/search/default.aspx?query=Visual%20basic%206%20encryption&catalog=LCID%3D1033[
^].
Cheers!
—MRB