Please post an image from disk management. You can go to disk management page by typing "disk management" in the search field inside start menu and selecting the option from control panel "create and format hard disk partitions". This will give us a clear picture of your system's drives both internal and external.
Your drive X: is showing as a removable disk, means it is connected to the system either by USB, eSATA or firewire. These types of disks can not be converted to a local disk. A local disk is a disk which is either connected to the system through a parallel ATA, serial ATA or SCSI.