So, turns out this is still an issue. The computer froze once during an iPod transfer and freezes EVERY time I run a Norton scan. It seems to be during processor intensive operations, yet when I run heavy MATLAB operations (MATLAB is an engineering software tool designed to crunch out lots of complex calculations) no freezing occurs. I thought it could be because the iPod is FAT32 and the hard drive is NTFS, but it occurs during other processes as well. A few times the computer freezes for just no reason, but mostly it has been due to a lot of multitasking, or the problems listed above. Sometimes when I suspect it will freeze I open up taskman.exe and put it on my screen so I can see it when it freezes, and there's no insane memory usage, just one process that's using a lot of my processor. Any ideas other than chkdsk / get a new OS? Fix the processor? I dunno.

edit: I thought about not having enough virtual memory - but I have 672 MB to 1344 MB allocated, versus a 512 MB DD RAM. Could it be that?