Vista - HP TX2000Z Tablet touch screen not working

Hi,

Configuration :
HP Pavilion tx2000z CTO NB
Genuine Windows Vista Home Premium with Service Pack 1 (64-bit)
AMD Turion(TM) 64 X2 Dual-Core Mobile Technology Gold Edition TL-68 (2.4 GHz)
12.1" diagonal WXGA High-Definition HP BrightView Widescreen (1280 x 800) w/Integrated Touch-screen
4GB DDR2 System Memory (2 Dimm)
NVIDIA(R) GeForce(R) Go 6150

NVIDIA GeForce Go 6150 Video Driver - 7.15.11.5682
This is the video driver version for my HP tablet(HP Website). But unknowingly I installed the latest version(7.15.11.7770) from NVIDIA through Windows update. And from that time onwards, my touch screen stopped working. It is not recognizing my stylus/finger.
I contacted HP care and they advised me to follow these steps.
1) Uninstall the latest driver and install the 11.5682 driver
2) Bios Flash
3) Calibrate
I am done with the first two steps but still my touch screen is not recognizing the pen. So I couldn't calibrate.
When I contacted the HP care again, they are telling it may be because of hardware failure. My notebook is working perfectly except this touchscreen.

Please anyone help me to solve the issue.

Cheers
Arun

Can you please tell me, what is the best way to install video drivers.

I tried in 2 ways
devicemanager ->display adapter -> Nvidia 6150 -> uninstall
Add/Remove Programs -> Remove only display adapter

After reboot, still it is asking me "Do you need to overwrite the files?

finger print reader also not working. I posted the complete details here

http://www.vistax64.com/general-disc...ws-update.html

please reply to that post.

Full system recovery solved the problem.