Do not sugest trialpay please
Cube 2 / Sauerbraten. fully ready to play, and totally open source. http://sauerbraten.org/
yeah here http://www.thegamecreators.com/?m=view_product&id=2001&page=Free
When you say you have it, does that mean you've bought it through Steam, or went and bought the cd?
Bought the CD from best buy. Portal works fine
Now, this is the most open question ever. If by FPS creator i assume you mean things like drag-n-drop interfaces, no logic coding, etc then the 3D game maker is a good one to use (google would be helpful). Of course, most FPSes are made using c++ code (or variants thereof) because its optimized for that kind of thing.
A good game development suite, of course, is Valves' Source SDK kit. It comes with HDR lighting, physics, AI; its like a god-damn swiss army knife but it takes a bit of know-how to make it work. Also, you'd need a copy of HL2 or another source game to get the SDK content, and those aren't free so it kinda defeats the object of the question really.
I have portal but it always says that the servers are busy when I try to download it, any help?