Thanks for your explanation. I did remove my drivers several time, but as you say, it seems that there are bits left of it. I used the tarball from nvidia and it seems that good rid of it properly. I couldn't install the tarball, though because it got more errors then previously, so I removed it again with yast2 and afterwards installed the rpms again (the one I had already installed and removed several times last night). Funny thing is that it suddenly worked. I don't understand why, for sure, because I removed it with Yast, I removed it manually and I tried to use the rpm for removing. I don't know why it suddenly works, but after that I tried 3Ddiag and it gave me nor more errors. I also checked with a OpenGL screensaver, which didn't work before, and this also worked, so it seems ok now.
In the meantime I also "solved" my problem that I can't set resolutions beyond 1280. I manually reconfigured the modelines for 1600x1200 and this works now also. I just have to dig out what the modelines exactly means, because I currently have a frequency of 75Hz. My monitor supports up to 150Hz (800x600 and 640x480) and at least 87Hz in 1600. BUt currently every mode is in 75Hz so I need to see how I can change that.
That's the nice thing about linux.
I can manually do something instead of having to rely on provided stuff.