Display Driver Crashing - HP Pavilion DV6500 - GeForce 8400M G

[shadez]

hi fellas...
i had installed new drivers for my graphics card about a month back. after a couple of days, the driver started crashing occasionally. not it has become frequent - very frequent.

laptop: HP Pavilion DV6500
gpu: GeForce 8400M G
OS: vista 32bit

1. i did a rollback of the driver and re-install - didnt work
2. there were almost no softwares installed after the driver was installed

so i installed uniblue driverscanner (unregistered). did a driver scan.
DS shows installed ver of driver: 8.16.11.8766
and available version: 8.17.11.9562

cool... but these morons, though they say free software, if you have to download the drivers, you gotto pay!

so, i checked HP support page. this is what they have:
NVIDIA GeForce 8400M/8600M GS Video Driver HP Pavilion dv6567cl Entertainment Notebook PC - HP Customer Care (United States - English)
driver version: 7.15.11.5665 A
strange, i had downloaded the previous driver from HP itself!

anyways, i check nvidia and this is what they have:
NVIDIA DRIVERS 257.21 WHQL
driver version: 257.21
now, what version is that???!!!

so my question is:
1. what am i supposed to do to get it properly working?
2. these HP service stations:
- are they good?
- will they do a complete re-installation of OS also? (i have original vista provided with the lappy)
- how much will they charge?

help...
thanks in advance...

[Neuron]

First i suggest that you run 'chkdsk /f' on the sytem drive.Also i suggest that you scan for any viruses 'coz they can corrupt files and can cause services to behave in unexpected manner.
Regarding the driver version 'NVIDIA DRIVERS 257.21 WHQL' is newer than what HP have.
The '257.21' represents the last 5 digits of the driver version.