Tried rebooting, reinstalling, everything.
Luckily, it works now, kinda. little. It still stutters a little, but it is playable now. I tried your suggestion and disabled everything in the background (found a few things that didn't appear in the task monitor, but were still there. Is that even possible?!), set AGP to x4, and reinstalled SCP again.
It now operates at acceptable levels, but slows down slightly when new ships jump in, Ani files play, and when the level first begins.
Other than that, it works...okay.
I wonder if, with the hyper-advanced card I have, I can improve performance someway. Any tips?
EDIT: Thanks Raa, for helping me...at least it works now. Thanks Cyker, for...uh...posting at all. A lot of people just view and leave.