Summarize:

You can also click the Start button and then type “folder options” in the search box. Select “Folder Options” in Control Panel from the resulting list. ” ”  ”   You should now be able to view all files and folders as well as drives hidden in Windows 7. . Look for a program named “ProgramData.” If you can see this, you are now able to view hidden files and folders. This is how you can differentiate between hidden and unhidden files.
Click on the Windows 7 Start button. Click on Control Panel. Click on “Appearance and Personalization. Click “Folder Options. Click on the View tab in the Folder Options window. Click “Show hidden files, folders, and drives” in “Advanced settings” and click “OK. Choose the “Show hidden files, folders, and drives” radio button in the “Hidden files and folders” category. Click “OK” at the bottom of the Folder Options window. Close the Control Panel window. Test this by navigating to the C:\ drive Notice that the icons for hidden files and folders are grayed out.