Hmm, DLNA is a different story. I thought you meant libraries that you had previously created or used.
If you don't need DLNA, you can turn that off:
Tools > Options > Media Network > Use Media Network > (unchecked)
You'll want to stop and restart MC for this to take effect. If you need to use DLNA though, I'm really not sure how to suppress the devices and libraries you don't want to see. The Media Network sub forum here might have some people who know more.
Good luck,
Brian.