Is there any way I can figure out if someone is performing a QoS through my router? I live in a house with 15 other people and everything is fine until one of them gets out of class and right that moment it turns to shit. Is there any way to counter/disable/destroy a QoS?

Packet sniff using a program like Wireshark (not to be done on public networks, btw). Filter by IP address and you can show that there are TONS of packets firing out of this guy's computer. Then once you can prove it, log into your router and add his mac address (which you should be able to determine) to the mac address table as a mac address that cannot be given an IP address.

Thanks, that'll do wonders.