I got pro tools today and i know from pro tools se that it will not open without having my M-audio fasttrack c600 connected, but it seems odd that you have to be constantly connected to your device.
The Fast Track acts as your "license key." If you're running Pro Tools 9 or 10, the iLok replaces this. You'll still need to have a "device" connected, if you don't want to use your C600 with it, though, which in this case, would be your sound card's ASIO driver (or if it doesn't have one, the ASIO4ALL driver, which is free to download).
If it's standard Pro Tools 9 or 10, then yes. You do need the iLok connected though. In the playback engine just make sure that your running on the PT Aggregate I/O. It'll run through Core Audio on Macs. Without the interface connected, you can't really have monitors though.