This page explains how to repair a sd card with a window pc. Have in mind that you are now deleting something.
Start diskpart (via Windows + R)
type „list disk“ to check sd card
„select disk x“ with x the number of your sd card. Be sure that you select the correct one.
type „clean“
type „create partition primary“
type „select partition 1“
type „active“
type „format fs=fat32 QUICK“
if sd card doesnt appear on explorer, type „assign“
Done.