check the internet settings in ie
Tools internet options
1) under connections delete all Dialup and virtual private network settings in the box. Then click LAN settings and make sure "automatically detect settings" is checked.
BTW, is the interent working on other applications (firefox if installed) MSN etc??
You could try accessing the routers control panel (usually
http://192.168.123.1.1) and try reconfiguring it or restarting the router.