Well......... the possible reasons could vary heavily depending on situation. Give some more info and you stand a better chance of actually getting responses.

(e.g.) Video card type/specs
 operating system
any usefull information that someone NOT sitting at your PC might not have access to.

Have you tried uninstalling, rebooting and then reinstalling and updating?

hm.. well didn't think to mention those because they exceed the recommendations. I use a 32-bit vista operating system. 2 MB of Ram, 2.4 GHZ , NVidia 8800 GTS graphics card (with the most recent drivers). Not sure what other information is necessary.

I've uninstalled at least 6 times now, restarted the computer several times, both with the game installed and uninstalled, and have updated the game three times with the same patch.  I even archived all the data using impulse...I'm relaly at loss

The first time I start it minimizes into the toolbar, then doesn't repsond. Each time after that it just loads up a black screen and still doesn't respond. Any ideas?

ah yes, 2 Gb... And yes, I can play many other games on my computer.

I've never... and I literally mean never, had a problem playing games on this computer before. Vista works just fine for me... but thanks for the suggestions.

Still don't know what to do though.

Sometimes it takes a while for splash the screen to kick in - try pressing escape a few times etc... just in case....

Check for any proprietary software running in the background i.e. printer or web cam driver or optimization software, stuff like that might interfere with the game initializing, if there is nothing like that then it could be that critical files on your game disk are corupted, completely uninstall (manually delete installation folder after) then download the entire game off Impulse, if that doesn't work I'd guess your SOL

I had this exact problem and running it in windowed mode fixed it. 

well, good news everyone, finally got it to work.. now lets hope theres no other errors that pop up.

I used a lot of the suggestions youu guys gave me. Set the compatibility to windows XP service pack 2. I also checked run as administrator. I don't know if this is some redundant thing only in vista, but there were 4 seperate locations where I had to go to and check a ox saying the same thing to run as administrator. merely checking one wouldn't check the rest for some reason... weird..

Anyway. I also went to task maanger and closed all unnecessary applications...for some reason my vista software was trying to download updates from apple computers..... Vista must be really bad to try that, haha.

Anywway, thanks for all the help guys, see ya in game!

I usually use LordTommy or LordTommy33 as a gamertag.... or I like potatoes.

Vista's not so bad if you don't mind customizing it.  Personally, when I get a new computer with Vista I immediately remove all propreitary software, and switch to manual all the services I don't absolutely need, or want.  End result, I love Vista and have never had any weird issues, even once I switched to 64-bit.