Browser can’t load pages?

I’ve been unable to load HTML pages in either Netscape Communicator (v4.76) or IE Explorer (v5.5) even though the ISP connection is valid. I can PING any site without problems. I’ve checked PROXY server settings (not used and not ON). I’ve reinstalled Windows 98 (2nd Edition), Netscape and IE thinking corrupt DLLs. I’ve removed and reinstalled DUN, removed, reinstalled and reconfigured TCPIP (numerous times). Virus checker is McAfee – using .DAT files just 2 updates old – can’t believe it’s a virus. Any other suggestions out there?