New IE problem - DNS Error?

New IE problem on my brother’s laptop:  Inspiron 9100.  He had internet connection one evening, then properly shut-down when done.  He turned on laptop the following morning and although he had verified ISP connection, the IE browser reply states:  "The page cannot be displayed."  He has Adware installed and the lastest scan performed showed no problems.  He also has 2005 Norton Internet Security (with Antivirus) installed.  His scans are performed on regular basis with zero problems to date.

Here’s where it gets interesting.....

Turning OFF the Norton Firewall will allow him to connect to whatever URL he enters,..therefore when looking at the "Properties" for IE browser while the Norton Firewall is OFF,..the Address: (URL) shown will be correct for whatever the URL is that he is trying to connect. 

For example: Address: (URL):  http://www.msn.com    

However, if he turns the Norton Firewall ON,…the Address: (URL) states the following:

Address: (URL):

res://C:\WINDOWS\system32\shdoclc.dll/dnserror.htm#http://www.msn.com

Please advise as to what the problem is and how to correct.  Any help would be appreciated.