NVIDIA is aware that some GeForce customers have reported Windows TDRs (timeout detection and recovery) while browsing the web with Release 280 and later drivers. NVIDIA is actively working with customers to address this issue. In the few cases where NVIDIA has been able to reproduce this issue (both on-site and working directly with customers), a complete manual uninstall of the driver and subsequent clean installation of the latest Release 285 drivers using the exact directions below has fixed the issue. We will actively pursue any issues experienced by customers after following the clean installation steps below.
NVIDIA Display Driver Clean Installation Steps:
1) Click on the Windows Start Button.
2) Select Control Panel.
3) Select Uninstall a program under Programs or select Programs and Features depending on the control panel view.
4) Double-click on NVIDIA Graphics Driver in the program list and follow the uninstall instructions. Click Restart Now when prompted.
5) After restart, if you have any remaining display drivers stored in your Windows directory, Windows may start to install a different graphics driver. If so, allow it to install the driver and then restart again when prompted.
6) Repeat steps 1 through 5 until the NVIDIA Graphics Driver version is 275.XX or earlier OR until there is no NVIDIA Graphics Driver reported under Programs.
7) Download GeForce 285.62 WHQL driver from:
http://www.geforce.com/Drivers
8) Although not required, you may disable any system monitoring tools or anti-virus software running in the background as they may sometimes prevent driver files or registry keys from being written correctly during the installation process. After a driver installation has completed, you can re-enable your system monitoring or anti-virus software. To begin the driver installation process, Right-click on the NVIDIA display driver package and select "Run as administrator".
9) Continue to the Install Options page. Select Custom install.
10) On the Custom install page, select the checkbox for Perform clean install. Click next.
11) During the clean installation the driver, follow any requests to restart your PC.
12) After the installation is complete, restart your PC one final time.
Note: These steps are only recommended for this issue and are not required for standard driver updates.
If you have performed these steps and continue to experience TDRs, please provide your system information, driver version(s) and instructions on how to reproduce the TDR.

http://forums.nvidia.com/index.php?showtopic=215256&st=0&gopid=1322910&#entry1322910