Workaround registration in a .exe

I have .exe file with a program written for me by a programer who unfortunately passwed away some time ago. Therefore I have no means to access the source code any more. The program used to work up until I had to reinstall my system and now it asks me for registration which I have no idea how to workaround (I am guessing its some kind of hash over the mac or PC serial number, it definately is not related with network server etc, as the exe is working fully locally).

So I need someone to disassemble/debug that .exe to findout how can I indeed workaround the registration. Note that I will only pay for the result.

please add APPLE as a prefix to your proposal