Option 2 : use -reindex as commandline option in your dash desktop shortcut behind 'target'
Does wallet get passed the 'can't open blockchain' error now ?
example :
Option 3 : delete everything in your dash data directory except backups folder, dash.conf file and wallet.dat file (make backup of wallet.dat file when wallet is not running and store in safe place)
You can use Dash bootstrap (see option 1) to speed up download of Dash blockchain