|What error message if any do you get when the internet drops out?|
Since you access via an ethernet connection provided as part of your apartment lease you should complain to the landlord. Do you get any "network cable is unplugged" messages? or "Limited or no connectivity"
These would be signs of faulty cable or connection between your PC and the Router.
If the internet simply stops responding your problem might be the quality of the internet connection and the number of users that are connected to it at any given time. Without any details on the type of internet connection and the hardware configuration of the LAN you are connected to there isn't much we can advise that would be helpful.
Goin' Fishin' (Some day)