Safari freezing over and over

Today after years of watching TV on my iMac using Safari it's no longer working. The page will be open but it's not active / working. I've restarted twice and reloaded more times then I can count. I've cleared my history and website data. No new software has been added to my iMac, nothing has changed, from the last update of Yosemite, to today. I'm beyond frustrated and really need to know if theres a way to defrag or clean my iMac using Apple only products so I don't break it. Help