How to fix Hidden extensions
Explorer's default settings in Windows 7 hide file extensions, as well as system files and folders.
To fix this, launch Explorer and click Tools > Folder Options > View.
Clear the "Hide extensions for known file types" to show file extensions, reducing the likelihood that you'll accidentally double-click on virus.txt.exe in future.
And as long as there are no novice users on your system who might go poking around in Explorer, I'd also choose to "Show hidden files and folders" as well as clear the "Hide protected operating system files" box. It's often important to see these files when you're troubleshooting, or following problem-solving instructions from someone else.
