Did you upgrade to Win7 or do a clean installation.
An upgrade would carry forward al the settings and instalations from your previous set up.
If so you willhave to remove whatever mail clients you have and then instal Thunderbird.
Samsung Galaxy S10 review: Hands-on
Alice Tye on blurring the line between fine art and illustration with Japan as her muse
Best free iPhone games 2019
Comparatif : iPhone XS vs Samsung Galaxy S10