If your .ISO and .IMG files are showing up as unknown files, you can reset their file type associations using Default Programs. Windows 7 includes the Windows Disc Image Burner, the default handler for .ISO/.IMG files allows you to burn a CD or DVD from an ISO disc image file.
.ISO file showing up as elby.VCDMount.1 file (occurred after uninstalling Virtual CloneDrive in a PC.)
Resetting Windows Disk Image Burner as the Default
1. Click Start, Default Programs
2. Click Set your default programs
3. Select Windows Disk Image Burner
4. Click Set this program as default, and click OK.