Use this free utility to uninstall Safari > Download AppCleaner for Mac - Uninstall your apps easily. MacUpdate.com
Then re download Safari from here > Safari 5.1.7
FYI.. if you are having problems with Safari, it's rare that just reinstalling the app helps.
If you still have problems, post back and describe what's happening ...
I'm so frustrated because I can no longer post ANYTHING to Facebook. I can comment but I can't post. Then, I'm going to the history to remove the cached pages and I should be able to sort them but they won't sort. This is after I've already had a glitch with looking at Facebook in Mozilla. Yes, you could say it's Facebook but I'm not having a problem on my Blackberry or iPad.
So, I thought uninstalling Safari might to the trick. Frustrated.