Here are the best steps to do, since you did some already here they are and there are 2 ways, keep your bookmarks and top lists the same, and second just get it working again and set it up again. (hoperfully you vote for best user : ) )And these are only if you test it in a new user and safari works fine in the new user! Otherwise, reinstall Safari. if the steps below dont work. It looks like a lot but really is not:
1. EASY WAY/ LOOSE BOOKMARKS ETC.If you don't care about the bookmarks and top list items, and the tabs work in the new user. then just follow these steps close all program including safari. Then go to the House icon, Library > Preferences > com.apple.plist and drag it to the trash. You can also take the user/Library > Preferences > Safari Folder and take the entire folder and drag it to the trash. This will cause you to loose only your bookmarks, top list items arrangements, history, etc. Then restart or log out and log back in and then launch Safari. It should look like it did when you first launched it, but you keep all the updates you did to it. And it should work if it did in the new user.
2. StILL EASY + KEEP SETTINGS! Go to the Apple > System Preferences > Accounts, then unlock and create a new user. Make it easy by calling it test and maybe use test as the pw or don't use a pw. Then run Safari and see if you have the same issues. If you do not + it works than it is an issue in your user account only and that the program does not need reinstalled. Log out of that user and go back to your user. To make it easy go to force quit and make sure there are no other programs running once back in your user.
~~ If it works in new user you will go to Safari on the top menu bar and go to File, export bookmarks. You can export them to the desktop, if you want to salvage them. Then go down and hit close Safari and make sure it is closed! Then click on the Finder icon if not listed next to the Apple in upper left corner. Then open a Finder window if not go to File and go to Open New Finder Window. In this window, on the left side in the middle you should have your username with a picture of a house. Click on the house with your username. Then go to the Library folder and then locate the Preferences Folder and find a lot of similar items, and you want to find Com.Apple.Safari.plist and drag this item to your desktop (main screen). While in the Preferences folder, find the folder that says Safari,if you want to salvage how your Top Sites. In this folder find TopSites.plist and drag it to the desktop like before.
~~ Then restart the computer. When you get back in launch Safari and then test the tabs to make sure they work. If they do then you may begin 2 get your bookmarks and Top List items back. 1st to do this you want to go to Safari next to the Apple and go down and hit close. Make sure its closed, Then open a Finder window as done before and then click on the house icon + open the Library folder, then the "Prefs" folder. Then take the item com.apple.plist and drag and drop it into the "Prefs" folder. It will ask you if you wish to replace the item with the older one, and say yes. Then in that same "Prefs" Folder go down and open the Safari folder and take the toplist.plist item and drag it into the Safari folder, and it should ask you the same question, again, so say yes replace
~~ Then launch safari and see if it opens to your normal top items, and the tabs still work. If they do then you will go to file and import bookmarks, and guide yourself in the window to your desktop or wherever you exported them to. Then open a tab, click on Bookmarks on top menu bar and hit Show All Bookmarks. It will show you a list of items on the left and a folder will be there saying Imported with the date next to it. Open that folder and put your bookmarks back where you wish to have them.
My email is listed and I can even talk through it if you want or need me to. I don't mind. So if any problems, contact me. Or Apple.