Yes it's possible that your wallet file was not fully committed to disk because of the crash. You should run scan disk on your hard drive to check for bad sectors.
Also if the hard disk is an SSD? Does this matter in any way?
Same thing applies. The file wasn't committed to disk because of the crash. Could be a problem with the disk or some other piece of hardware in your system. It's not an electrum problem.
Ok i got help also from Electrum dev on IRC channel yesterday, everything clear now.
I supposed it was an OS related issue and not an Electrum's one. Better know.