The swap file is normally a maximum of twice physical RAM - 30GB is way too much for a swap file (unless she has way too much physical RAM. of course)!
Is it possible that she is using some form of peer-to-peer file sharing (knowingly or not)? That could rack up large disk usage pretty quickly.
The security precautions you have in place would suggest that it isn't a zombie PC hosting files, but P2P could be allowed even with all the precautions you have in place.
SD