there is a way to turn off ICS, sorta kinda. but it's not really quite "off". your system is never really the same once you turn it on. right click on all your network connections, pick properties, advanced tab, turn off ICS. it is essentially a DHCP server. universities call it a rogue DHCP server. and they say you might have to re-enable it for home networks once you have turned it on.
or reformat your computer to fix the ICS problem.