problems restoring backup

hello there 

i am new in sambapos. i installed sambapos4 in my takeaway.was working good.few days ago i installed microsoft sql express 2014 since then it was not loading :i uninstalled sambapos and microsoft sql express 2014

i installed sql express 2012 and sambapos again.it loaded this time.i tried to restore backup file but says ( current database type doesnt match backup type)

i dont know what i am doing wrong. i dont want to loose all the data and work i did.please help me