X64 refers to 64-bit and X86 refers to 32-bit. You don't need both, but it's also possible you don't have both and instead the Registry just wasn't cleaned up when switching from 32-bit to 64-bit (if you've had this computer for 4+ years). The text is hard to read in your screenshot, but this information may appear after the version number. For example: 107.0 (64-bit) When uninstalling, be careful NOT to remove any data if you are offered the option. The uninstaller may well permanently flush ALL of the data (i.e., data belonging to the other installation would also be unrecoverable). So Just Say No to deleting data.