Cannot access some valid url's despite knowing they are valid
I have two computers, an ASUS with Windows XP & a HP with Windows XP sitting side by side. I just reinstalled Windows XP on the HP & it updated with hundreds of Microsoft updates. Now, when I try to access some sites I get the "Oops! Firefox could not connect to..." message. No reason why, my firewall is not blocking any sites & then I switch over to the other computer & access them right away. As a matter of interest, I also have Chrome & IE 6 installed & it does the same thing with them
You can find the connection settings in Tools > Options > Advanced : Network : Connection
If you do not need to use a proxy to connect to internet then select "No Proxy"
See "Firefox connection settings":