I think the best option is just to abandon the whole programm as I cannot get seem to get my data back.
Upload image file with the file dialog or by dragging and dropping images onto the dashed region
http://libguides.northwestern.edu/c.php?g=114874&p=750371 (this, btw., is a very ineffective way to solicit help. If you're going to quit using Zotero anyway, why should I spend time trying to help you?)