Folder didn't regenerate, even through command prompt. Instead of a white sheet it now shows a white rectangle with a blue square and grey lines. I guess it's suppose to be a PC screen.
Try resetting the icon cache to see if it resolves the issue. You can do this by navigating to the %LocalAppData%\IconCache.db file and deleting it. Afterwards, restart your computer to let Windows rebuild the icon cache. You can get there by pressing Window+R, then type in %LocalAppData%\ Find the iconCache.db file (back it up by copying it somewhere like a usb drive) then delete the original file. Restart your computer.
Try updating your windows to the latest build. You may need to click the "check online" link. If that doesn't work, google "windows update assistant" and see if that helps.
Oh, blizzard has a fix for that, you should look it up...here's what a quick search produced: us.forums.blizzard.com/en/blizzard/t/battlenet-taskbar-icon/3078/2
