User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:75.0) Gecko/20100101 Firefox/75.0

Steps to reproduce:

Installed FF 75; it offered to make it the default browser; accepted and led to a Windows program selection page. scrolled to browser clicked but FF is not listed.
shut down and restarted computer with same result.

Actual results:

Still cannot choose FF as the Windows default browser

Expected results:

FF, chrome and edge options offered

Thank you for the report, could you please describe how did you install Firefox? Was in installed using official installer, MSI or unzip?
Also, if you use an antivirus, probably would be a good idea to list that aswell.
Meanwhile, let's set the correct component.

FF was acting strangely, so shut it down and deleted the software. Downloaded a new copy of FF and installed it from Mozilla web site. Use Norton safe web as antivirus. It is running the newest update.

Because this bug's Severity is normal and has not been changed, and this bug's priority is -- (none,) indicating it has has not been previously triaged, the bug's Severity is being updated to -- (default, untriaged.)

S1 or S2 bugs needs an assignee - could you find someone for this bug or adjust the flag?

The bug has a release status flag that shows some version of Firefox is affected, thus it will be considered confirmed.