How do I get rid of unnecessary drive letters??

Using Windows 7 Home Pro. On my Windows Explorer, I have all sorts of unnecessary "Removable disk" drive letters that I sometimes have to keep sorting through to figure out which is my flash drive. Yes, I know I should be able to recognize which one it is, but it can be annoying. I would like to remove all those extra "drives." I believe they all think they are CD drives or flash drives, because if I click on one, they ask me to "insert a disk." How can I get rid of these? There are SEVEN: labeled "Removable disks H,I, J,K, M,N, AND O."

fwiw: I tried the solution I found online, which takes me to diskmgmt.msc, but the extra drives do not show up there.

Thanks for any help.