From what you're saying, it appears the databases became corrupted. However, this can't happen without a proper reason, and I suspect the cause to be a corrupted application or another program installed on your computer.
At this point, the only thing you can try is to recover the files using a recovery solution. For example, Recuva is an application that's used to recover files that have been deleted or corrupted because of various reasons.
Download Recuva: http://recuva.software.informer.com
Save the package, install it, and then point it to where the databases were stored. Enable Deep Scan from the wizard menu to increase accuracy. When found (files marked with a green filled circle) right click them and choose another partition for recovery.