IE Browser failure

My son is running Win98 with dialup internet connection.
For the last week his browser fails to open ('page cannot be displayed'). His Outlook Express is receiving and sending emails OK. Whatever address is typed into the address bar it still won't open a site. Have checked all the obvious options and have run Adaware, Spybot, CWS and nothing shows up as wrong, have also checked firewall settings and even turned the firewall off. However at the top of the browser above the toolbar the following is displayed - OWS/System/shdollc.dll/dnserror.htm
Would appreciate any help please (in simple terms
Many thanks

 

Above problem is now fixed