How can I retrieve my Photoshop Elements 13 Editor?

I'm brand new to this forum so excuse me for not knowing the rules. Here is my problem.

My Photoshop Elements 13 will not open. I last used it 3 days ago, since then I have not been able to work with it.

I've considered buying 2018 since 13 is no longer available. The format looks the same but It has so many extras I won't use.

Would anyone be kind enough to tell me what is OS?

Or advice as to what happened to my Elements 13 and/or how to fix it?

Thanks,.Dee B