Hi!
Sounds like you've copied your existing Firefox/Thunderbird profile
after reinstalling the software. In this case, ReminderFox thinks
that the reminderfox.ics file where it stores reminders is in a
different location to the new profile location.
Could you please
- confirm that you did copy your profile,
- advise whether you have ReminderFox installed in Thunderbird
or Firefox, and also
- advise how confident you are making changes to your computer.
If you're impatient, and confident, have a look at
https://groups.google.com/d/msg/reminderfox/HwV70TTc7XQ/CrTdjUETGAAJ
and the following posts for the basic procedure that I'm currently
expecting you'll need to follow.
Make sure that you have a copy
of your reminderfox.ics file before doing anything. If you're
using Firefox, and don't mind reinstalling all your Add-ons, it may
be easier to just refresh your profile - see
https://support.mozilla.org/en-US/kb/refresh-firefox-reset-add-ons-and-settings
Paul