Boot drive help!

[Jab00]

Okay so I installed Mountain Lion when it was first released and attempted to (and thought I succeeded) make a bootable thumb drive. Today I decided to test it out because I have been contemplating changing up my HD only to find that although the files were all there and could be seen when logged on it would only show a circle and slash combo when I attempted to boot from it. So I went through my time machine backups and found the ML install file again and spent some more time today attempting to make one. I tried making it via Disk Utilities as well as making a USB and DVD install disk via the Lion Diskmaker program. Has anyone else had these problems or care to contribute some solutions? I have been following the directions explicitly and keep hitting this problem :/