I have perused this site ever so briefly, so I apologize should this issue be old hat.
I have a home network with a Linksys Wireless-G broadband router (Model No. WRT54G). My internet connection is via satellite, and I have the router hard-lined into my desktop, which I'll denote as computer 'A'. All the other computers (two desktops and two laptops) on the system have wireless-G adapters. All the computers except my desktop, 'A', work flawlessly on-line. What I mean by this is that there is never an issue with time-out errors or server not found problems.
I cannot say the same thing about my desktop. Just about every time I try to acquire a webpage I receive the "Server not found. Firefox can't find"...blah,blah page. If I hit the "try again" button at the end of the message, the same page is instantly returned. I receive similar results using Internet Explorer. My only recourse is to use the cmd.exe: ipconfig/flushdns. If I use this I usually acquire the page immediately or after two or three attempts. I should say that there are times when I am able to go to several websites without the error; however, I receive the server not found page more than the website I am trying to visit.
I use TrendMicro's firewall and antivirus protection. I don't know what more I should add - except that I am not overly computer savvy, especially with networks. Hence, should you feel obliged to assist, assume you are talking to a child and please use small words.
Thank you for your time and assistance.