It probably means that the computer is not using a proxy to connect, and you may have a host file installed on your computer under your account that allows access to only those sites. If you have admin access try creating a new account and see if you can get to other sites.
Log in as admin. Chrome is really just IE with a Google skin. You need to disable proxy settings in IE. Tools- internet options- connections- lan settings
Whose computer is this?
At the same point as you log in as yourself. If you don't know the admin password though, you're out of luck...
If it is your computer, you are probably the admin. try right click on the internet explorer icon on your desktop and choose run as administrator and then try the lan settings.
You can find the connection settings in Tools > Options > Advanced : Network : Connection<br />
If you do not need to use a proxy to connect to internet then select "No Proxy" do this
go here -----> http://isitup.org/
only these two sites or all sites?
I assume you are using windows 7 and these two sites are blocked on this computer.. or may be the internet service provider.. try google translate.. type url into the translate section such as www.facebook.com and translate it into any language say french see if it's working by this method.