First of all, I'll give you my Laptop's specs. 
Windows 7 
Intel Core2Duo @ 2.13 GHZ 
4 GB RAM 
NVIDIA GeForce GT 230M 
NOW 
Onto the fun part. 
I play the game, I'm driving around, and out of nowhere, the game crashes. I edited the Handling.dat file, or whatever it's called, but I replaced the edited one with the original. I edited some cars using the newest SparkIV (6.8), and that's it. I forgot to save the original cars though... 
Does anyone know why my game is crashing? 
It's the latest GTA IV, latest patch.