Hi, this is, I think, new. I can't find anything on this and all 501/505 message posts are related to Windows XP not 7. But, I have a 501/505 error message in my Windows 7. Funny thing, it is a problem with all my browsers (IE and Firefox) and I cannot access any website with the www. prefix. Urls without this prefix works fine. The only thing I can think of is that I downloaded and installed a Java update yesterday. Did this cause the 501/505 error problem? I also tried following the steps recommended by Microsoft for XP (http://support.microsoft.com/kb/811262). No joy. Is this a virus? Help.