Controlling browsing on PCs

Dear,

Server: win 2012 server
PCs: windows 7 ultimate
(The server is just for data backup; no remote desktop, no mapping, nothing much).

I need to be able to control browsing on the PCs: e.g. Deny access to social media websites for example.

Please advise.

Is this in a business setting or a home environment?

For homes, I would use OpenDNS and let it deny the social media category.
It is not perfect, but it should help.

For businesses, I have no idea if OpenDNS fees are reasonable.

Thank you dear; will check it out.