We'll ill tell you what i had to do to get my sli to work on my i7 build with my 280 HC16's.
- First step Uninstall all drivers and files (where you zipped the nvidia files).
- Shut down
- Before starting up unplug the sli bridge. to make sure i unplug my 2nd videocard.
- Than Turn on & reinstall the drivers.
- Shut down.
- Replug in the sli bridge and power.
- Turn on. Once it's loaded right click > Nivida preferences and select advanced. It should have Sli option in the left hand Conner under phyx's