I have recently installed opensuse 12.1 and 12.2 over my opensuse 11.1 machine where I previously had the desktop effects working.
I did not like either so I re-installed opensuse 11.1, now I cannot get the desktop effects re-enabled.
I have a Nvidia 8600 GT video card.
I have tried the following 2 Nvidia drivers: NVIDIA-Linux-x86-180.22-pkg1.run and NVIDIA-Linux-x86-310.19.run .. neither lets me enable desktop effects.

Any suggestions ?

This "may" work...
Logout of the desktop and press Ctrl+Alt+F2 and then login as your usual self.

Ctrl+Alt+F7 and re-login.
Check Desktop Effects.

Thanks, but I already had the enable-compiz file
Further research and consulting my old notes provided the answer.

I had to download the Nvidia-Linux-x86-173.14.22-pkg1.run driver from the Nvidia archives.
Ctrl-Alt-F2 to switch to a console > log in as root > init 3 to switch to run level 3 (login as root again) then:

sh Nvidia-Linux-x86-173.14.22-pkg1.run -q .. once done, then .. sax2 -r -m 0=nvidia

init 5 to get my desktop back .. enable desktop effects in control center .. and BAM .. wobbly windows and desktop cube is back

I have to get more involved in Linux again, my current job has me dedicated to legacy NetWare

that antique driver is NOT supported in the X11 in opensuse 12

you HAVE to use the opensource "nouvau " driver

also that is used BY Default on opensuse 12
if you change it out with the .run driver
YOU must rebuild the boot image to use the nvidia driver
BUT
seeing as the 173 driver is not supported any longer in x11 .....

also searching the nvidia site your Gforce 8600 GT uses the 310 driver
and NOT the 173 for the very old gforce5 card

you might want to read the opensuse documents on the nvidia driver
http://en.opensuse.org/SDB:NVIDIA
http://en.opensuse.org/SDB:NVIDIA_drivers
there is a "one click" install

Usinf the ".run" is called " the HARD way"

and for new users i would Recommend "The repository way"