I have found this topic already: [Help]Bootable USB Disc back to Normal USB
but it did not solve my problem.
I followed the directions on this tutorial: Install Windows 7 From USB Drive/Pen Drive
to make my 8GB flash drive bootable to put Windows 7 on my sister's computer which has a DVD drive that won't read my Windows 7 DVDs for some reason.
Now I need to return my USB flash drive to normal, except that it only shows up as a disk drive. I can't right click and format it as the computer wants me to insert a disk to format. I am also unable to format the flash drive using Disk Management, where it is also showing up as a disk drive, but with no media inserted. What am I missing? I hope I have not forever ruined this flash drive.