Most times it is a video driver issue.
 
Go to Nvidia.com and download/install their latest driver.
 
Or check on this site for different versions of a det drivers.
 
Move any PCI cards that you can to other slots (swap them around).
 
If the sound is integrated , try using a PCI soundcard.
 
I had a game that would move at the speed of molasses until I dis-abled onboard sound and installed a soundblaster card.

Thanks for your advice, I have tried det drivers 41 42 44 45 for NVIDIA and XP the 45 driver seems to be the latest I think, I do have a PCI sound card 5.1 surround sound, there is an onboard AC97 sound thing integrated but I disabled that and use the PCI card (I tried using the AC97 and it still freezes)!
 
I see it slowing jerking a little when moving the plane around then about a minute later it freezes with stuttering sound, I tried having no sound acceleration and that made it even worse for some reason!
 
Maybe it has to do with the AVG virus killer installing drivers in some places even although I always disable it before trying to play the game!
 

I have been having the same prob with FS2000 - irregular clicking sound, and double sound when I switch between desktop and full-screen mode; and frame rates suddenly dropping to 1.3/sec or something ridiculous at every critical moment. The following steps (as recommended above) seem to have worked:
 
1. Download latest nVidia driver
2. Download Directx 9.0b
3. Uninstall AVG 6.0 (there doesn't seem to be any way of disabling it) before installing nVidia driver and Directx
4. Disable onboard sound using the jumpers on the motherboard
(My motherboard (ASUS CUV8X) has an onboard AC97 audio codec, and I also have a Soundblaster Live! 5.1; they were conflicting)
5. Reinstall AVG 6.0
 
Strangely, a few clicks still remain in the sound, but the graphics seem steady at around 13 frames/sec - hardly fast (but then my PC is old), but certainly more playable.
 
Thankyou
 
xMymblex

I found this thread while trying to figure out why all of my MS simulators are freezing.
 
Since I installed SP2 none of my Microsoft Flight Simulators work FS 2002 Pro, CFS2, CFS3. I can fire them up. But, usually my system freezes up within minutes, often this problem is immediate. I don’t have problems with any of my other apps (though I’m still installing software after a reformat and a reinstallation.)
 
I’ve looked in several flight simulator forums as well as the Microsoft Knowledgebase and found no answers.
 
I have a feeling that the problem is related to my Nvidia drivers, which are new. However I’ve tried several older drivers and still had the same problem.
 
FYI I've got the new Nvidia drivers installed now (actually I think that this may be conflicting with SP2). My CPU temp is usually under 120. All my Simulators worked just fine before SP2. Anybody have any ideas?
 
 

I just got Need For Speed Underground 2... I installed it and it was working fine untell few minutes into the game and computer locks up or freezes. And sometimes just restarts by its self... I tryed turning down the grafics but did not help. I should have or have a good computer. It plays HL2 fine. i got ATI athlon blah blah not going to check in on that.. :x So if any one knows what to do please email me at LordNikio@gmail.com
 
Maybe there is a patch to fix this proplem.. An update for the game I tryed lots of things,.. Im going to ask my dad if he has any idea.
 
But other than that its a great game!