...for users of Grisoft's AVGFree antivirus. You may have noticed that suddenly three files are listed at the end of a virus scan. The files are not infected, the program merely tells you they are changed. It's nothing to worry about. It's probably just a Windows Update or some new program you installed.
The files concerned are user32.dll, shell32.dll and ntoskml.exe. You can make AVG stop nagging you about these files by accepting the changes. To do this, launch AVG Test Center. Press the F3 key. When you are prompted about how you want to handle the file's new status, accept the change. It will ask you for each of the files and once you've accepted the change, you will no longer panic at the end of your scans when AVG says, "The sky is falling, the sky is falling."