Ok I tried that and when I right click the partition "Delete" is not available to me.First of all you can't just simply right click and delete a drive. You can access the files on the drive and then delete the files. If the drive is optical or an external hard drive than you can't delete that drive without disconnecting it.
If the E:\ is a partition of the internal hard drive than you need to "manage" the drive.
start->right click on Computer and select Manage. On the next screen select "Disk Management". Now right click the partition you want to delete and select delete. After that you can right click any other partition and select "extend volume" to use the remaining space.
I hope that helps!
I had downloaded this online then I used an ISO program which may be where this was partitioned.On our oem computers there is a recover D:\ and even when it is not in use "Delete Volume" is greyed out as well.
How did you create the partition in the first place exactly?