Do I need to post the errorlog?
The freezing up issue has made it so that I can't even get past my current mission (4th or 5th runthrough, now).
I may be able to help you. Assuming you're running an AGP-based system, try reducing the AGP-X factor to half of its rated speed. On my old system, I used to get lockups with anything but the very newest drivers, then it just got to a point where I couldn't stop it. Then, I had a major data loss incident, requiring a total reinstall. When I started playing again, I found that Freespace ran much slower, but I didn't have any lockups or an occurence of a certain texture anomaly. Eventually, I found out that the AGP drivers never got installed, causing it to behave as a PCI video card. Restoring the drivers accellerated the game, but the locking and texture anomalies returned. I then dropped the AGP factor from 4X (max) to 1X (the only other option with the controls I had) and the locking and texture weirdness went away, without any speed loss.
Some months later, I upgraded my core system (CPU, MB, RAM, & VC) and returned to playing Freespace, but the freezing bug returned. I reduced AGP from 8X to 4X and the freezing went away, with no noticable performace loss in Freespace or any other program. It even gave windowsXP a stability boost. It seems that sometimes, FS doesn't like it when a system and card are running at their full AGP spec.