I have a PC with windows vista and an NVIDIA Ge Force 8600 GT graphics card. I tried to update the driver on Saturday and but the install was unsuccesfull and now windows keeps on trying to update the software and telling me timeout period has expired.
And my screen resolution has changed.
You're probably using a pirated version of Windows. Buy a legal license and it will solve your timeout period problems.
For the video card, go to Add/Remove Programs and uninstall Nvidia drivers and reboot. Install the new drivers after the reboot. Video cards drivers are more sensitive it can be risky to install a new one on top of an existing one, it's safer to uninstall the previous drivers first.
But are you sure you downloaded the right drivers in the first place? Did you get them from the Nvidia website?