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.
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.