1. Power off the router. Unplug it from the wall. Wait a while.
Plug it back to the wall. Power the router on. Wait until all the lights are lit properly. It will take a while.
Restart the computer.
Start up in Safe Mode.
http://support.apple.com/kb/PH14204
3. Empty Caches
Safari > Preference > Advanced
Checkmark the box for "Show Develop menu in menu bar".
Develop menu will appear in the Safari menu bar.
Click Develop and select "Empty Caches" from the dropdown.
3. System Preferences > Flash Player > Advanced > Delete All
Press “Delete All” button under “Browsing Data and Settings”.
4. Install Adobe Flash Player.
System Preferences > Flash Player > Updates
http://get.adobe.com/flashplayer/
Download it and quit Safari from Safari menu in the menu bar.
Follow the prompts to install Adobe Flash Player.