Umm this doesn't work easily at all. Its not a valid PE file. XP won't run it. I guess it requires 16 bit real DOS. Where did that go ? command.com used to be the go.. Anyway for anyone out there needing this as well, here is the solution. Lets say your compressed file with SZDD header is called FILE.EX_ and is in C:\ Simply run the following command from a prompt expand FILE.EX_ FILE.EXE Voila.