Make your Pendrive Bootable by following few Steps.
Conditions....
->You must have plugged in the Pendrive in USB port.
->You must not have any important data in the Pendrive.
->You must have to check the disk part no. in the computer managment
Working...
Step 1.
(after pendrive plugged in the computer's USB port)
Go to search bar and search for "CMD" like this

Right click on "Command Prompt" and click on run as administrator and a popup of User Accounts Control will display, confirm that by click on Yes button.
Now you will get a tab of CMD like this.

Step 2.
Now type 'CD\ ' and press Enter.
Type 'DISKPART' and press enter now you can see two or more disk parts.
Step 3.
select any disk by using key word 'SELECT DISK 1' or whatever your "Removeable" is.
Step 4.
Now type 'CLEAN' and press Enter.
Step 5.
For creating partition you have to use a key word 'CREATE PARTITION PRIMARY' and press Enter.
Step 6.
Now type 'FORMAT FS=FAT32 QUICK' and press Enter.
Step 7.
Wait and for a while until complete formatting and then type 'ACTIVE' and press Enter.
Step 8.
Now type 'ASSIGN' and enjoy with your booted Pendrive.
Note:- don't forget to leave your comment of satisfaction.