Shoutbox

if you are using xp based machines, located the SAM and System files and calculate the user hashes, then use [name of password cracking software] to find the passwords. If you are lucky, the system admin password is on each and everyone of the systems. That way, you can have full system access. That still leaves the issue of getting blocked from websites.

As for VNC, my school blocks access on every port except for 3128 through which they access the gateway, and then the internet. Therefore VNC can have issues, depending on how your school's network is set up.