This software is portable and free. You can use it to locking or unlocking your files. By using AJ File Security you can add the files which you want on the list and lock all of them by just one click. Also you can see many of diffrent extensions in the program's window (mp3, txt,jpg, bmp, avi, mpg, mov, pdf, html, htm).
After locking a file, the software that you want use to open the locked file,will show an error about file damaged but you can see your locked files in AJ File Security.
You can set a password to enter the software.
Windows Server 2008