First, before any of the other stuff below. Go to Internet Explorer. Tools ->options->connections->LAN settings and check the box Automatically Detect Settings hit apply or OK and close IE and restart it. Worth a try.
Note: For the following to be of any use you will need to know if your IP address needs to be static or dynamic. For the cable co. it's most likely dynamic, I don't know about DSL. You may want to call your provider to find out if it's supposed to be static or dynamic and if it's supposed to be static then what is it.
Try.. start->Control Panel->double click network connections. Right click on Local Area connection.-> select properties. Select Internet protocol Tcp/IP->properties.
Are the circles for Obtain an iP address and DNS server automaticaly ticked off? If they are, then you're set up for dynamic IP and DNS. If they're not, write down the numbers in those boxes and try changing them to automaticaly, couldn't hurt.
Did you remove a stand alone router from your setup when you put the new modem on?
Note: For the following to be of any use you will need to know if your IP address needs to be static or dynamic. For the cable co. it's most likely dynamic, I don't know about DSL. You may want to call your provider to find out if it's supposed to be static or dynamic and if it's supposed to be static then what is it.
Try.. start->Control Panel->double click network connections. Right click on Local Area connection.-> select properties. Select Internet protocol Tcp/IP->properties.
Are the circles for Obtain an iP address and DNS server automaticaly ticked off? If they are, then you're set up for dynamic IP and DNS. If they're not, write down the numbers in those boxes and try changing them to automaticaly, couldn't hurt.
Did you remove a stand alone router from your setup when you put the new modem on?