HELP! Can't connect to DSL!!

I'm looking for anyone that can help me!

Recently, my Macbook has been letting me connect to the internet for only about 15 minutes and then it will go out and say that "this page cannot be found." Once I restart it, I am allowed to use the internet for fifteen minutes again but then it will go out. It's weird because I can connect to my schools internet but once I go home I can't connect to any form of DSL (Ethernet or wireless). I previously had Leopard and then installed Snow Leopard, and at that point I got my internet completely back. A week later it went out again. Of course this has all happened about a month after my Applecare warranty expired. Can anyone help me with this please? Thanks for your time!

You need to tell us what equipment you use for the connection. Is it a combination wireless router modem?
If so, you need to set up PPPoE authentication on the router, but Turn Off PPPoE on your Mac. (Configure using DHCP on the Mac.)

Sorry about that! I am using a Zoom five router. It's ethernet. I have DSL through my university and they set up the router according to the modifications that they require. Any ideas how I would turn that off on my router since they have restrictions on that? Let me know if there's any other information that you need! I'm fairly clueless when it comes to specifications and anything regarding DSL.

You need the university to help in this case.
Sounds like you're not a registered user in their system.

I brought it in a couple weeks ago when it first started and they said that everything was fine and the modifications that the university needs are in place. They made a point of saying that it was my computer. I lean towards believing them because when I installed Snow Leopard, it worked perfectly for a week. Then recently, my computer went back to only allowing me fifteen minutes of internet access through my ethernet. :/