GTX660: problem with new graphics card

Folks,
Been running happily with GeForce 8600 GT for ages, but upgraded my card to run four monitors (!").
Unfortunately, unless I run in vesa mode I can't get anything going at all. It is rather weird because even when booting only part of the screen is being used.
When I go in to MCC, I can't see any option for GTX cards. I tried GeForce 400 and later, but then it won't boot at all, with or without using the whole area of the screen. :~/
Anyone able to help me please? Bear in mind I have been using the proprietary drivers. IS it possible I need drivers so new they are not in the repositories?
Thanks!
Been running happily with GeForce 8600 GT for ages, but upgraded my card to run four monitors (!").
Unfortunately, unless I run in vesa mode I can't get anything going at all. It is rather weird because even when booting only part of the screen is being used.
When I go in to MCC, I can't see any option for GTX cards. I tried GeForce 400 and later, but then it won't boot at all, with or without using the whole area of the screen. :~/
Anyone able to help me please? Bear in mind I have been using the proprietary drivers. IS it possible I need drivers so new they are not in the repositories?
Thanks!