What kind of links are you trying to open? Do you open them in an external application and have Firefox set as the default browser or are those links on a webpage?

Wish I could tell you exactly what I was trying to open. I think they were Windows links in pages I was reading. Never seen this before. Not a problem on my desktop; just the laptop with new installation. Firefox is set as default browser. If I get more info, I'll let you know.

Considering you didn't say what links no one is going to know just from reading where and what those links are and what they do. A screenshot of the error site would help those reading see or know what is causing the issues.

This is the link I was trying to open:

This usually happens when Windows doesn't recognize the file type or protocol. Try checking if you have the right app installed to open it. If not, searching for a compatible app in the Microsoft Store might help. Also, right-clicking the file and selecting 'Open with' can sometimes let you choose the correct application. What kind of file or link are you trying to open?