haha, do you have to study on the PC? If so, turn the internet off while you study and leave it off for at least 1 hour or however long you want to study for.
Hmm, lets see what else...
- have a clean desk with only the things you need on it
- turning off your mobile for the same time - just leave it to your message bank to pick up calls
Not sure what else you can do! Good luck!