Safari won't launch

I am hoping someone can help me. I was having problems logging on to a site and the tech that was helping me was not a Mac OS tech and had me clear my browser history. Now Safari won't launch…or I should say it quits before it can completely launch. I know the problem is the fact that Safari prefs were set to open up all the tabs that were open when it shut down but now that the history is gone it doesn't know what to do. I tried to restore the previous version from my time machine but it tells me I can't change or delete Safari because it is needed by the OS. So what can I do to fix it??

Try resetting Safari from the Safari menu, "Reset Safari". Check and uncheck those items that you wish to be reset before doing so.

Safari won't stay open long enough to reset.

I got it. I had to start up in safe mode in order for safari to stay open so I could reset it.

Well done! Thanks for letting us know what worked.