A couple of things:
Most people should not need to mess with the pagefile settings. The defaults should work fine. And these days, I have not been able to find any reason to get something like a Quadro. The GeForce 9600GTS outperforms the Quadro FX1500 by quite a bit, and it only costs about $150.
But neither should have a big impact on regens for a nearly-empty drawing. Virus software should not impact regens, either. There really was not enough info given to help diagnose this problem. Computer specs? Version of C3D? (Oh, I see in the sig it's C3D 2009.) In any case, it sounds like there is something strange happening.