Try Safari in another user account. If you don't have one established, help here > OS X Mountain Lion: Create a new user account
If the same problems exist in that account, that's an indication the startup disk needs repairing.
Log back into your admin account.
Launch Disk Utility located in HD > Applications > Utilities
Select the startup disk on the left then select the First Aid tab.
Click Verify Disk (not Verify Disk Permisions)
If repairs are necessary, restart your Mac while holding down the Command + R keys so you can access the built in utilities in OS X Recovery
If Safari functions as it should in the test user account, log back into your admin account, see if Safari will launch long enough to try the following...
Try troubleshooting extensions and third party plug-ins.
From your Safari menu bar click Safari > Preferences then select the Extensions tab. Turn that off if there are any installed. Quit and relaunch Safari to test. If that helped, turn extensions back on then uninstall one a time to test.
If it's not an extensions issue, try troubleshooting third party plug-ins.
Back to Safari > Preferences. This time select the Security tab. Deselect: Allow all other plug-ins. Quit and relaunch Safari to test.
If that made a difference, instructions for troubleshooting plugins here.