Ubuntu 12.04 LTS with NVIDIA Quadro series drivers problem.

I recently installed Ubuntu 12.04 LTS with 3.2.x kernel version. I'm using NVIDIA Quadro 6000 graphic card. After installing Ubuntu 12.04 OS Ubuntu is not booting in normal mode, screen is freezing. when i goto recovery mode with disable graphics ,ubuntu 12.04 is booting. For that reason I tried in internet NVIDIA forum suggested upgrade kernel version 3.2.x to 3.4.x, so I upgraded. After upgrading, ubuntu 12.04 with 3.4.x version is booting in normal mode. Next I changed my graphics card Quadro 6000 to Quadro 4000, bco'z my app is required two different windows.So I want to install two graphics cards. So first I uninstall Quadro 6000 drivers and shutdown my Workstation and replaced two nvidia Quadro 4000 graphics cards. Next I power on my workstation, it is not booting with ubuntu 12.04 with 3.4.0 kernel version and recovery mode also. But it is booting with 3.2.x kernel recovery mode without graphics. So tried to install nvidia Quadro 4000 drivers in this kernel version and rebooted my workstation. After rebooting also same problem came. Here any drivers problem or OS kernel problem, Please give some suggestions. My Workstaion Configuration ---------------------------- Workstation : HP Z8000 Processor : Intel Xeon x12 2.8GHz RAM : 16GB DDR3 HDD : 1TB Thank you Nani