convert from NTFS to FAT and from FAT to NTFS

To convert NTFS to FAT, you need to back up the data from the drive, reformat the drive, and then restore the data.
Click the "Start" button on the taskbar. Followed which, right click on "My Computer" and select "Manage".

In the "Computer Management" window that opens, click on the (+) before "Storage"

Click on the "Disk Management" option.

Right click the drive you want to format and choose "Format" from the context menu. Here we choose the D drive. 

Using the File System drop down list, choose the file system you want to use for the drive. In this case, we are choosing a FAT file system.

The size of the drive you’re formatting dictates the choices available in the File System drop down list. Only those file systems that can handle the drive you’re formatting are listed.

Click on "OK"
And you are done with the conversion along with the formatting. Reboot the system for the effect to take place.

 
 convert from FAT to NTFS

 A simple one step on how to convert FAT file system into NTFS:
Click on "Start" menu on the taskbar and then click on "All programs" followed by "Accessories" and then "command prompt"
                                 

In the "Command prompt" window that opens, type this:

convert d: /fs:ntfs

This is to convert your D drive into NTFS. If you wish to convert another drive to NTFS you need to replace the drive letter "D" to "E" or "F", the drive that is applicable.
 

Thats all. Conversion may take a while and once completed, you need to reboot your system for the effect to take place.