First, follow the steps as given in the installation guide that comes with the Tesla C870.
The key is to configure your PC to first run X-windows without the Tesla C870 and then add the Tesla C870 and add it to the Xorg.conf file. NVIDIA provides a tool called nvidia-xconfig that helps in automatically generating this file. To use this utility, follow these steps:
If the system has a non-NVIDIA graphics card, then configure X to run with the non-NVIDIA graphics card. Then add the Tesla C870 and run nvidia-xconfig.
If the system has a NVIDIA graphics card, we recommend the same procedure as above or you can directly run nvidia-xconfig.
If these two steps do not work, then run “nvidia-bug-report.sh” as root and post the “nvidia-bug-report.log” on the CUDA forums for Linux to get additional help.