Curious problem with QE/CI for GeForce 6600 GT

Today I decided to upgrade to 10.5.3, so I downloaded the installer with ASU (newest version) and it patched the package succesfully. After that I installed it on my "Test-Partition". I restarted and installed the new (amd-patched) Kernel. After another restart everything worked, but there was no QE/CI. No problem - edited the NVDAResman.kext and NVinject.kext and restarted again. Then I started XBench, system went like a charm and I decided to do the same procedure on my main system, but this time a little bit faster:

I installed 10.5.3 (the patched one I used before) and installed the kernel. Restart - everything worked out of QE/CI. No problem again I thought and then I did the mistake I think: I didn't change the NVDAResman.kext and NVinject.kext, but used the ones from my test partition. After a restart my only avalailable resolution was 1024x768, system didn't detect my graphics card and there was (off course) no QE/CI.

At this moment I didn't panic, but beat myself for being so inpatient while upgrading on my main system. I used the kexts from the time between 10.5.3-Upgrade/Kernel install and my try to fix graphics. But they didn't work, too. I tried installing the both kexts by Pacifist, but nothing worked. I never got at least a true resolution (not to mention QE/CI). So what was my mistake? Was it the unpatience not to reboot after everything? Or something else? I don't think, that its such a big problem I have, but I don't know how to fix.

Greetings,
-crawle