OS: openSUSE 12.2 (64-bit) KDE
Problem: after installing the NVIDIA drivers (304.43) the repository way, the computer fails to power off after shutdown (whether from X-Window or shutdown -hP). Log shows XXX: System Halted. The problem was reproducible on two different computers with different NVIDIA cards (GeForce and Quadro). Changing from Plymouth to Bootsplash did not help.
Workaround: In boot specification change acpi=off to acpi=oldboot
So you might want to consider installing the nVIDIA proprietary video driver the hard way which is newer at 304.51 right now. I have some blogs on the subject:
Installing the nVIDIA Video Driver the Hard Way - Blogs - openSUSE Forums
AND
LNVHW - Load NVIDIA (driver the) Hard Way from runlevel 3 - Version 1.46 - Blogs - openSUSE Forums
AND for a faster system, look to a new kernel version 3.5.4 you can compile with this:
S.A.K.C. - SUSE Automated Kernel Compiler - Version 2.78 - Blogs - openSUSE Forums
Thank You,