I live with my girlfriend and a guy who just moved in,we've lived there a year longer than him he doesn't tidy up after himself and constantly demands to use my tv, xbox and wii (i own them all!) without my consent how do i politely get him to stop?

If he demands, you don't have to be polite, just civil. Tell him clearly that you don't want him using your personal stuff without asking. There is also no problem telling him to clean up his mess. Remember this for your next roommate ('cause this one might not last very long) and write down a list of "rules/ requirements" to discuss with the person and have him agree to before moving in. Keeps you out of messes like this. Good luck and get to telling him.

I tell him look this is my stuff not your and I want you to leave it alone and if you can't respect me and that I have asked you not to touch my things then you have to find another place to live.

GROW A PAIR! ;-) You could keep these valuables under lock and key. You could write polite post-it notes and leave them all about the apartment. You could rig them with explosives. How could a guy "just move in"? Just move him out. Problem solved.