Unable to Play Any Games on Vista

Vista can play games as long as they are compatible with your PC hardware and/or Vista or maybe if you can run the game in a compatibility mode. 

You should first start with the gaming section of the forum and include what games you are trying to play so the gamers can help you with that to start with.

If the Video on the PC works with everything else, it's not a Video hardware problem (this forum section).

the games i've tried are Star Trek Bridge Commander, Star Wars Empire at War, and its expansion(forces of corruption) Neverwinter Nights, Soldierfront, Spider-Man 3, and Star Wars Jedi Academy. Everything else works perfectly(not games) like surfing the web, typing documents, watching movies etc its just any game that requires going to full screen, causes the screen to either go into power saving mode, or go black and nothing works, I've contacted dell support and chatted with them online twice but still the error occurs

There is always the possibility that some of these older games will just not work on Vista.  Some games will have patches to make them work so you could look for that.  I actually have one of your games mentioned (Star Wars Jedi Academy) but I have not tried it on Vista.  I had it on an XP computer previously.  Vista does have a game compatibility site showing games that are compatible and games that are not.  Of the games you have, it showed that Spider-Man 3 was compatible but for the others it was unclear.  Some game manufacturers will recommend disabling all of the background processes from running through your Task Manager in order to get a game working properly.  Also, some of these game publishers have good support sites and can be contacted at no cost or will have FAQ's to help.  I have contacted the game publishers before when things were not working correctly and they have been able to fix the problem. 

Some of these games could possibly run on integrated graphics.  You could pull the card out and try it to see if it works.  If so, you could have an issue with your card and there is also the possibility that some games just do not work on the ATI card.  If I were you, I would download a more recent game demo and see if you have any issues playing it.   Game Demos

Lilmandoboy26, I work with the Windows Outreach Team, and would like to suggest that you check here: http://www.microsoft.com/windows/compatibility/Default.aspx  and see if your games are listed on our official compatibility website.
RickR