Brenda,

I've been using my Ausus laptop with Ubuntu as its OS & Firefox as its browser for 10 years now.

Power outages here in SW PA are common. And awhile back I had the entire electrical system, from the meter to the breaker-box, replaced in my house & was without power for 10 hours.

And thru none of that has my browser ever lost any data.

It certainly puzzles me as to why you experience the opposite.

What you might consider doing is backing-up your PC regularly. I do that weekly. So if I ever do have a major problem with it, like a major loss of data, I can readily reload my laptop's system so it's operational again.

Which PC type are you using? Which browser & operating system?