Sounds like you're capturing to the same drive as your OS/application drive? If so, that's a bad idea.
saving while capturing is also not really advised as I don't believe your saving the file that's being captured anyway if it crashed. The file is open while being captured and wouldn't close if it crashed, so the file would be hosed.
Course, I may be reading this wrong.
General idea might be to clean your media cache - sounds like it might be on the full side. Check out preferences/media...
Dennis already said it, but a single disk is not enough. Minimum requirements are a DEDICATED 7200 RPM (e)SATA disk for capturing. Add to that the fact that your system is dead slow (at least 50 times slower than a fast system) and that one should not do anything else during capturing, and that the system may not be tuned at all for editing and disaster is waiting to strike.
Have a look here: Adobe Forums: Guide for installing and tuning a Vista... which also applies to Win7, for a band-aid. It will not solve the issue of an extremely slow CPU, possibly integrated Intel graphics, which should be avoided at all times, shared memory, which is another no-go and the lacking disk setup.
Why is your file manager is open during capture? Ideally, no other apps but PP will be running, and you'll be doing nothing else but the capture.