Help pls, cannot open Firefox browser for Windows 10 Pro, clicking icon says my profile missing. Alsoo some folders properties show the target as an A:\Users path rather than expected C:\Users but the path is 'grey' cannot be edited.

Help please, cannot open Firefox browser for Windows 10 Pro anymore, clicking icon advises my profile is missing. How to fix ? Ive also spotted a number of folders properties are showing the target as an A:\Users path rather than the expected C:\Users but the path is 'greyed out' and cannot be edited, help much appreciated