Router makes internet drop??

Hi

We have a dell inspiron 530 desktop computer running XP profeessional and a dell inspiron 1501 laptop running vista. These are both linked to our internet connection through a dell wireless 2350 router. Everytime that the router has an internet connection, it drops within 30 mintues. We know this is the router because at the moment we are running internet straight into desktop. This problem started when we were trying to get file sharing a printer sharing (which we still haven't managed to do) to be set up through the router. Does anyone have any ideas/ suggestions? Thanks.

Rob.