Planograms missing from the project

Hi,

This has happened to me twice and without the proper documentation I am lost.

I have a project that have about 16 tabs, each representing a planogram. I was working on one of the planogram exporting items from another planogram on a different project in order to get the right image sizes...hope you with me so far. Now, the computer is getting really slow by this time, so, I saved what I was doing, closed the Space Planning and restart the computer. When I get the system up again I was missing more than half of the tabs (planograms) from the project I was working on.

Can somebody tell me why this is happening?

Is there any way to backup the files I'm working with?

Can I copy a .psa file from the windows explorer and paste it on another folder without missing references to libraries and products?

Thanks,

Miguel