Don’t Let it Happen Again!
One way to prevent this sort of thing from happening again is to use a built-in Excel function to automatically create back-ups.
Go to File > Save As and click Tools. In General Options, choose the Always create backup check box. Now whenever a save is made, the backup will also be taken, a useful insurance.
You might also consider instructing Excel to create a recovery file. This file will be used to recover your document in the event of another crash or outage. To create this, go to File > Save As and open Tools. In Options, go to the Save tab and mark the Save AutoRecover info every check box, adding a value at the end.
This value will be in minutes, so you could set the autorecover to take place every 5 minutes, for example. Meanwhile, in the event of your PC having a corrupt or suspect disk, use the AutoRecover save location box to enter a file path for saving your recovery files.