The other topic was closed. This is a fresh subject unrelated to your previous topic.
In Firefox click on
Tools>Options>Advanced>General Tab then tick '
Always check to see if Firefox is the default browser'
Then click on '
Check Now' and select '
Yes' to the question asked.
Click
OK - job done.
I will close this topic now as Altrea pointed out it is not really XAMPP related.
If you have any XAMPP for Windows related issues in the future then please feel free to open a new topic and we will do our best to help out.
Good luck.