Windows 7 - Unable to delete volume

I'm trying to delete a volume so I can extend a partition. However the option to delete volume in disk management is grayed out. How do I fix this?

Here you can see I can't delete the E: partition

Hi there, you cant delete this partition because its a system partition and its marked as Active.
Just next to the E:\ partition, there is some unallocated space. You can right click on the partition you want to extend and then click Extend Volume.

I want to delete E: so I can extend C:. I basically want the whole drive to be just one partition. However I am unable to delete the E: partition. Btw E: is not marked as active.

Sorry. Yes the partition is not marked as Active but it does contain operating system files. Could you 1st extend the E: drive and use all the unallocated space to extend it? Once its extended, it must give you an option to delete the entire volume.

I tried that and it still doesn't work...

Screenshot:

did you already try to login your Windows 7 DVD and during the installation, one of the step is ask about partition, and over there you can delete it.

Your E: partition is the System partition which means it contains the files needed to boot windows. Should you delete that partition, you'll need to do a Startup Repair in order to boot windows.

Startup Repair

You can try using a 3rd party utility like Partition Wizard to delete or use Diskpart. Heres how to use diskpart.

Partition or Volume - Delete