When I try to open Safari, a window open, but never loads, then it appears to crash and window suddenly disappears. I have updated operating system and cleared cache. What can I do to fix this without losing the windows I have open and/or saved?

It would be better if you can please re-post with a screenshot, in order to understand the phenomenon better. Images/pictures speak louder than words. 

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With the limited information that you have provided, It is hard to even guess the problems faced by you. 

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Please re-post with detail so that someone else can help.

As much as I wanted to keep all my tabs, and go manually close the ones I no longer needed, I was tired of Safari not working. So, alas, as recommended (after trying all other suggestions), I selected "Clear History and Website Data" and said "yes" to closing all tabs. Safari immediately started working again. Sad I had to lose so much searching...

Other options I tried was restarting phone, using data instead of wifi to load, and clearing website data without clearing history or closing tabs (under settings>safari>advanced). None of these worked for me.