Hard, but try OLLYDBG, dunno if it will work on Gamegaurd tho, i doubt it.
Otherwise you would need to reverse engineer it, wich is extremely hard if you don't know how the program got compiled, so it would be basicly impossible if you can't code in the language it was coded in.
Darkness cannot be defeated. It can only be hidden in the form of hatred
Make an edit for Gamemon.des so it refers it to a different string or whatever? Make it so like it's still there but it doesn't detect it. It' like changing it from front to back, if it's open AVA will close, if not it's open.