Q: safari does not open a lot of sites just hangs up

Please try the trouble shooting steps given in these articles.

Safari 9 (El Capitan): If Safari can’t open a website

https://support.apple.com/kb/PH21431?viewlocale=en_US&locale=en_US

If Safari doesn‘t load a page or webpage items are missing

https://support.apple.com/en-us/HT204098

If this doesn’t help, please run EtreCheck and post the report here.

    http://etresoft.com/etrecheck

    Download it, open Downloads folder, click on it to open and select”Open”  in the dialog to run it.

    Click “Share Report” button in the toolbar, select “Copy to Clipboard” and then paste it when you reply.