Me: By The Way, I'm intrigued. Why does restoring Windows make you lose your data? Never happened to me.
Him: Well, some things I would never have believed would happen to me either.... but they have done, they do.... and we learn to live with them, I guess. You never had a PC crash to the point you had to revert to 'factory settings' - good on yer!.
Me: Sure, but that's not the hard drive. The data is always perfectly safe on the hard drive.
People panic and re-format or FDisk or similar. When the PC has to revert to factory settings, it is the PC that is reverting (usually people play around with the BIOS), and even if in the BIOS settings one changes the description of the hard drive, that still doesn't change the hard drive.
I can twiddle BIOS to my heart's content with NO hard drives physically present in the machine. The hard drive can, after all, be pulled out of the machine and a different one substituted. I do it all the time. I have two hard drives literally dangling from cables as we speak.
Reformatting the hard drive after "Factory Settings" is rather like people trading in the old car because it ran out of petrol, or one of the tyres went flat.