Update your Riva TNT2 Model 64 (I didn't see a Riva TNT 64 model, so I think you mean the TNT2 card) drivers from nVidia's website (although the game runs so it's possible that the video card isn't the cause) and update the drivers for any possible hardware on your PC (sound card, etc.).
Then try rebooting and playing that point through again. If the crash resurfaces, check all the processes on your PC and stop all that you don't really need to check if any of them might be the cause. If it doesn't help, then it's either a bug in the game or that you're possibly playing a warez'ed version that might have its own problems. Check Half-Life 2- related message boards.
DO NOT INSTALL THE DRIVER FROM MS, that's worse than doing monkey business.
But since it starts up and plays until the third checkpoint, it runs on your PC. So updating (although is recommended - at least to a Radeon 9600 or something) is not that necessary.
I cannot say more from the provided information.