defzons,

I cannot provide any technical advice because I don't possess the technical competency. I would say that whatever technical solution someone may provide will not solve this problem because the root cause is a disagreement over usage.

The other person that lives in the appartment (he is using the LAN port on the router) Unplugged my wireless card from my laptop ( God damn ) Because he was about to play a counter-strike match (Heh?)
You have stated that you all share the broadband connection, hence I presume the cost. Therefore, everyone has an equal right to this connection. Your flat-mate has absolute no right to be either adding nor removing hardware without your express permission. The crux of the problem is due to one person's selfishness. Unless you can all agree, or all get separate broadband connections and a physical lock on your bedroom doors to prevent unauthorised access, no technical solution will sovle your problem when everyone has physical access to the router. It's futile providing a technical solution which will not solve the problem - you've all stated that you share the cost equally therefore all of you should have equal access.

Personally, if I lived with someone who acted in such asinine fashion, then I would either:
1. Install my own broadband connection and a physical lock on my bedroom
2. or my preferred option, either tell my flat-mate to pack up their sh$t and don't let the door slam on their ass on the way out, or I would leave

If the situation has got to the stage where hardware is being removed and the connection is being hijacked, then I would move in with more mature and trustworthy flat-mates. If it's not your [shared] broadband connection then it will be another issue.

Take my advice, either manage to sit down with your flat-mates and draw up a tenancy agreement or one of you has to move out. If you cannot have mutual respect and trust with the people that you live with, then it's time to get a new apartment.

Regards,
Riotgirl