I downloaded the game yesterday, it started up fine and I played for a few hours before I went to bed.Today I installed the most recent patch, and now when I try to start the game, I see a loading icon for a split second then nothing happens and it doesn't load.It won't come on and I've uninstalled and reinstalled about 3 times so far.I'm running it on windows xp.Can someone help me?

Prove me wrong, but isn't the GoG version up to date already? There were quite a few times when updating already updated GoG games resulted in not being able to run these.

Or are you talking about the unofficial patch?

Yeah, there should be no need to install any patches, unless you are installing the unofficial patch.

What patch did you install? Like Lilim said, GOG applies the latest patches for their games, so no need to do it yourself.
Also, after reinstalling the games three times, have you always reinstalled this "patch", too? Or the GOG-provided game itself won't start?