The gmax installation files are IN the SDK folder when you first install it. You need to copy them to somewhere else because in the process of updating to SP1a and SP2, it gets removed and they are no longer in the SDK folder (as I said in an earlier reply). ;)

The FSX_gamepack for gmax is still in the SDK after you have installed SP2 (SDK\Environment Kit\Modeling SDK). It is only gmax that has been removed. You can get all the gmax files from TurboSquid HERE.

The following files are all you really need.
gmax12.exe
gmax12_help.exe
gmax12_tutorials.exe
library.exe

From this TurboSquid forum post:  "get the well known and accepted workaround to get the registration HERE or HERE" - I recommend the first one.

There is nothing illegal about the registration workaround. For some unknown reason (to me), the normal way of registering doesn't work. I was lucky enough to get mine registered before this happened, but my official registration is not accepted by gmax anymore so now I have to use this workaround. TurboSquid are the ones who distribute and support gmax now and they are the ones who allow you to download and use workaround (well they certainly haven't put a stop to it in the last 5-6 years since I first found it).

Mark