Runs horrible with my MSI GeForce 8600GT!!!!!

I can't believe that a 2005 game doesn't run smooth at all with my 8600GT video card The problem: I'm quite new at this, so I don't know how to explain it well. The gameplay it's not fluid... the player moves are like "mechanic". The same thing happend with DivX movies when you don't have the right codecs: the video runs, but it gets stucked for less than a second... every 3 or 4 seconds!!! That makes the hole game unplayable . I tried with all the drivers... same result. I tried with all the configurations possible in the Nvidia Contro Panel (and selected the minimum graphics option)... no change. Games like Virtua Tennis 3 and Winning Eleven PES 2007 run smooth, The only one givving me problems is NBA Live 2006. And it's not a monitor problem because the TV (S-Video connection) shows the same problem.
MY System specs:
MSI K9 NEO V3
AMD Athlon X2 4000
2GB DDR2 OCZ
MSI GeForce 8600GT OC
Any tip? Any advice?

Have You tried to adjust the gameplay settings? Game Speed in particular..please check the speed..thanks goodluck..

how large is the memory of an 8600GT?

The 8600GT has 256 DDR3. I will check the game speed later in home. Thanks for the tip and the answers.

No, the game speed isn't the problem. Same thing happends no matter the game speed. I'm really dissapointed with this

What is your actual FPS when you run the game(download fraps at www.fraps.com if you don't know how to check it)? Do you have VSync and Triple Buffer set to 'on' in the detail settings? They can smooth out the rendering of games sometimes.

Your 8600 is more then worthy to run Live 06. One thing could be hard drive fragmentation, but I'm just tossing that out there because it can cause "hitching" in FPS games when turning corners. I highly doubt that it could be a cause of the problem.

Maybe it's because of your X2. That is a dual core processor, I believe. Try opening the Task Manager(CTRL+ALT+DEL) and setting the processor AFFINITY to only one core, or the other core.

Thanks for the tip. I finally got it. I minimize the game, hit alt+ctrl+del and noticed that one aplication was using 50% of the system resources: FIREFOX!!!! The curious thing: I don't have internet at home, so... I don't get it. I hited "finish task", and 5 seconds later firefox came back . So, I uninstalled Mozilla and... magic. The game runs smooth now. Thanks to all of you for helping me.