Single Player doesn't work

[foododaddy]

So I have Windows 7 64bit. Single player doesn't work. Just starts the busy mouse for about 3 seconds and exits.

Is GPNet required to play? I ask because I can't create an account with it either.

Sigh..

[Fear Itself]

Having the same problem.

[BirdOPrey]

I don't know if this is the same problem you are experiencing, but I too had issues of starting the game. Since I'm using a laptop, I have 2 video cards that I may use one is Nvidia GTX 555m 3gb and the integrated video card. Using the Nvidia control panel, I set space siege in the panel to use the integrated video card. (I'm using windows 7 64bit)

This fixed my problem and allowed me to play the game (albeit not at the highest settings). Maybe this will be enough information to somebody with a more technical background to provide a better fix.