have a look in disk admin, (type disk management in to the win7 search box).
You'll be able to 'shrink' E: however I suspect that the space will appear after E: and not before it. If it appears before it you may be able to expand C:
Back it up to a separate disk first!!!.
But the real question is why do you care enough to want to change it, yes it might look nice to all be on one drive, but having your documents, music etc. on another partition can be helpful.
You can install programs to e: store everything on E: (then if C: gets trashed you've still got it).
If you pick these things up quickly and have the knack and are not too scared about losing things then go ahead use disk management, play and learn (its how most of us go to where we are) if you need help with every step then its probably not for you and you should leave well enough alone, wait till you buy a new HDD and deal with it then. I'm running C:win7 d
rograms e:data and am more than happy with that.