Impossible to access certain websites
The problem of access can come from the presence of a firewall. If a firewall is installed, check its configuration settings.
Possibly try to locate the hosts file under c: \ windows and check its contents. Depending on the version of Windows:
C:\WINXP\system32\drivers\etc\hosts
C:\WINNT\system32\drivers\etc\hosts
C:\WINDOWS\system32\drivers\etc\hosts
C:\WINDOWS\hosts
You cas open the file with
Wordpad.
Normally it contains only lines beginning with #, except:
127.0.0.1 localhost
If other lines appear, they can prevent the connection to the sites because they are forcing an IP address for guests involved!
You can try checking this:
http://en.kioskea.net/faq/sujet 2093 introduction to mtu