.steps:-
1.  Insert your USB drive into your system and wait for it to be recognized and install any necessary drivers.
2.  Fire up disk management and re-assign the drive letter it was given to “A”.

Start up disk management by clicking Start and typing diskmgmt.msc


Right-click the USB drive and choose to assign driver letter or path.

Assign it to letter “A”

Accept the warning message

Now your USB drive is “A”

3.  Run Syskey and save encryption to USB Drive “A”

Click Start and type syskey followed by hitting Enter

Syskey launched; Click “Update”

Choose “Store Startup key on floppy disk” and click “OK”

You’ll be prompted to enter your diskette. Make sure your USB drive is inserted and writable.
4.  Reboot and have fun.  Don’t lose your USB disk!  Also, to revert this, you can run syskey again and choose to store it locally instead of “on a floppy disk”.