Me and my friend brought two Tesla card for one of our HPC project. To my surprise after installing the new driver (Win7 64bit) for the Tesla C2075 compute board, Nvidia Control Panel won't start and gives out an error "You are not currently using any Display attached to an Nvidia GPU". But the windows device manager was listing it properly as a working card and there was no error in the system logs. It was really puzzling.
After some time fiddling with the settings and Googling I found this Autodesk forum, which says that by default the new Win 7 driver sets TCC bit ON. So I started a command line in administrative mode and navigated to C:\Program Files\NVIDIA Corporation\NVSMI folder and issued the following command to disable the settings.
nvidia-smi.exe -dm 0
A reboot was required. And guess what the control panel started working as it was supposed to. Woooh ! it was a great relief coz I thought the board might have gone bad.