Privacy and vpn to work off of a personal home pc?

I VPN into a work pc off of a personal pc from home. Wondering does that mean all the files on my personal home pc are visible/accessible on the work network? If so, is there any way short of buying a completely different pc for work to prevent access to my personal files? I am on Windows Vista Home Premium (64-bit)|||not usually. A vpn just connects to your work systems. just disconnect from the vpn when your finished and all connections to work will be disconnected.