Video Problem

Hi all and thanks in advance for any advice. I'm running the following system ASUS A8N SLI Deluxe nForce4 SLI Chipset SATA RAID AMD Athlon 64 3500+ Newcastle 1024 MB (512MBx2) PC3200 400MHz Dual Channel DDR MEMORY Corsair NVIDIA Geforce 6600 GT 128MB 16X PCI EXPRESS VIDEO CARD 80GB SATA-II 3.0GB 8MB Cache 7200RPM 200GB SATA-II 3.0GB 8MB Cache 7200RPM SB Audigy 2 Super Alien 500 Watt PS I'm currently using the 77.77 Nvidia drivers My problem is intermittent. Sometimes while swithcing to VC view I end up with the top part of the screen in VC view while the bottom remains in 2D view. I've run every test I can think of using SiSoft and have found no problems that I can see. I defrag on a regular basis using O/O. I'm hesitant about changing drivers as I have read nothing good about the 8 series drivers. Craig