You have to decide which drive is the one you want to select by the drive size. That is normally easy to determine but if you have two drives of the same size, then it will be difficult to determine which one it is. You may have to disconnect one of the drives that you don't want to delete so you will know which one it is that you want to delete.

If you have a flash drive that you want to delete the partition, do the following

1. Run Command Prompt as Administrator (click link for instructions)

2. Type diskpart and press Enter

3. Type List disk and press Enter

4. Look for the partition that matches your USB drive (You will do this by looking at the size) (Make sure you select the right one or you will delete the wrong drive)

5. Type Select Disk # (substitute  the disk number that corresponds to your USB drive (that is indicated from the list disk you just did for the #))

6. Type list partition and press Enter

7. Type Select partition (input the partition number lsted in step 6 that you want to delete)

8. Type Delete partition and press Enter

9. Type partition # (select the partition number you want to delete. Use caution and verify you are deleting the correct partition)

10. Type Delete Partition and press Enter

If that doesn't work, you can use the clean command of DiskPart

1. Run Command Prompt as Administrator (click link for instructions)

2. Type diskpart and press Enter

3. Type List disk and press Enter

4. Look for the partition that matches your USB drive (You will do this by looking at the size) (Make sure you select the right one or you will delete the wrong drive)

5. Type Select Disk # (substitute  the disk number that corresponds to your USB drive (that is indicated from the list disk you just did for the #))

6. Type list partition and press Enter

7. Once you are sure you have the correct drive selected, type clean then press Enter