Ok fella's lets see If I can make this understandable, so bear with me.
I have Counter Strike Condition Zero protected by the same protection, now when I installed it, it not only put it with the Steam games but also created a desktop icon, now if I go thru steam to play all I have to do is open My Games with-in Steam and then choose CS:CZ and start, it authenticates thru Steam and starts without the disk. Now if I choose to start the game from the desktop icon when I double click it asks for the cd, now my guess is that it is asking for the cd to complete authentication since I didn't attempt to start the game thru the Steam application. I hope this makes sense. I got Half-Life 2 thru Steam so I have no way to verify this other than the same happens for Half-Life and Counter Strike (the first ones) since I used the cd's for those install's, go thru steam no cd required, start from desktop icon the cd is required. I hope this makes sense.


Look at the first guide in my signature, it will show you how to clean yours and make it perfect, as long as you have a fairly reasonable one to start with.

Scan the install directory, see if it give anything from there.

if you use steam you can log into your account from anywhere to play, it will even download the needed files and games if they aren't present where you are at.