It seems like I need to use BT3 on a laptop to teach a bit about IT security at my school, and I'd need to be able to use a projector to show this to a large audiance, how would I best procceed to do this?
The other option would be to run BT in VmWare.
A third party security audit is the IT equivalent of a colonoscopy. It's long, intrusive, very uncomfortable, and when it's done, you'll have seen things you really didn't want to see, and you'll never forget that you've had one.
Maybe a stupid question but does anything display on the projector when you first power it on?
If you don't try press Alt+F4 and/or making sure the external display is not disabled in the BIOS (either press F2,F12 or ESC to enter depending on the system).
If you still do not see anything it a issues with your laptop not BT