Desktop Effects not working after upgrading to 4.2 [solved]

[eamner]

Hello.
Something strange just occured. I upgraded to KDE 4.2 (from 4.1.4) and the same night after I did it, all the desktop effects were working (like transparent windows, 3d screens when doing ALT-TAB, etc) but now, but the next day, I upgraded kubuntu again (using adept) and now none of the affects are working! The "enable effects" option is enabled. I disable it, and then enable it and nothing changes. I don't get any error messages.
What's more strange: my OpenGL screensavers aren't working now. I just get a black screen. They used to work perfectly (specially after installing the 180.22 nvidia drivers... I have a geforce 7300GT).
Any help will be appreciated.

[eamner]

Re: Desktop Effects not working after upgrading to 4.2

Anyone?
This can't be too hard... must be something obvious but I don't know where to look at.

[casperh]

Re: Desktop Effects not working after upgrading to 4.2

Have you enabled the new driver?

sudo nvidia-xconfigure

[eamner]

Re: Desktop Effects not working after upgrading to 4.2

Casperh:
Thanks for your answer. I run your command and after that, when I tried to enable the desktop settings, I got an error. It said something about an error in the xorg file.
But after this, I decided to reinstall the nvidia driver from scratch. Happily after the reinstallation, my desktop settings are enabled and working! and so are my opengl screensavers.
I just noticed something strange while installing the driver, at some point I got this error:
"Error: File '/usr/lib/xorg/modules/extensions/libglx.so' is not a symbolic link."
...anyway I just clicked OK and the installation continued normally.
Thanks for the help.