Windows 8 froze, but eventually responded again. The next time I tried to turn on my computer, Windows 8 told me it had encountered errors and would attempt to fix them...then it went into BSOD. When I refreshed the laptop using its built-in assistance, I lost almost everything--files, apps, etc. When I tried to see if I could find them somewhere on the drive, as refreshing isn't supposed to delete files, search turned up next to nothing. Unfortunately, it turns out this is because "C:\ is not accessible. Access is denied." Under its properties, C drive is listed as having 0 bytes used space, 0 bytes free space, and 0 bytes capacity.

Based on the issue description, it appears that you are unable to access C drive.

Please go ahead and take ownership of the drive, check if it helps.

I would suggest you to follow the steps outlined from “Issue 1: I get an "Access Denied" error message when accessing or working with files and folders” in this link, this would help you to take ownership of the drive.

http://support.microsoft.com/kb/2623670#method4

Here is what will happen when you refresh your PC:

Your files and personalization settings won't change.
· Your PC settings will be changed back to their defaults.
· Apps from Windows Store will be kept.
· Apps you installed from discs or websites will be removed.
· A list of removed apps will be saved on your desktop.