I think this is a virus and I want to get rid of it. Help!
What happens when you type the youtube or google website is that showing an error or any other websites being opened or not?
If that got error like "Blocked by Firewall" which means that the some websites are blocked by the your Administrator once contact the him to resolve the problem.
if you are connected to the internet through the router you need check your router settings where it is configured to visit some websites only. If the Router firewall blocked all the websites go through the manual of the router to unblock the router where you can access all the websites.
May your system is installed any firewall or the privacy control software once you need to check add/remove programmes that is located in the control panel.
If you were administrator you can remove the unwanted programmes.
There are so many ways to block the websites but how the websites are blocked it can be known by the error when you type the web address.