How can I find Inno Setup Decompile ?

[nando2002]

you can use Universal Extractor (google for it) which contains "innounp". A command-line tool to unpack inno setup installers.
Even giving you the source to recompile, it won't give you everything like pre-compiled code and the visual aspect the original installer has.
But in the other hand, after extract you can play the game directly from the {app} folder without need the registry values.

Try it - it's the only tool available you have far now - and then check the results and what you can do with them.