Scripting

start diskpart and try
select disk 0
list part
(search for the number of the recovery partition)
select part X
(X is the number of your recovery partition)
format quick
(get more format options like volume name or filesystem with help format)
assign Y
(Y is the letter you want to use)
exit

now you can apply the wim with image x to the letter

if you want to put this in a script, just put the diskpart commands in a text file line by line and call diskpart like this
diskpart /s yourfile.txt

Ok, I type in LIST VOLUME and I see that Volume 1 is my C: drive. I then type in SELECT VOLUME 1 then LIST PARTITION. I then see 2 partitions. Partition 2 has an '*' in front and this is the Primary C:\ drive. Partition 1 is a Hidden partition that is the 10GB one I need to manipulate. How do I format and/or assign a drive letter to this hidden Partition?

what I am trying to solve is this: We have a 10GB partition on thousands of machines and we want to copy to this partition the OS.Wim file and app packaged software that together make up our Windows 7 image. So if a user needs to reimage their machine they can.

Thanks.

try this (on a test machine!)
SELECT VOLUME 1
SELECT PARTITION 1
FORMAT QUICK
ASSIGN X (or the letter you want to use)

Um thats an OEM partition. That's what you called it. OEM are created by the manufacturer and can not be assigned a drive letter and are hidden. They can't be manipulated. I use Dell systems and all machines have also have a OEM partition, though significantly smaller. Because they are hidden, they can not be assign a drive letter and because of that, they do not appear in WindowsPE.

Let me ask you this. Short of a new blank hard drive, if all your machines have this partition, why not leave it alone and not reapply it?

Im not quite sure what your OEM partition does since its so big, mine only includes diagnostic tools. If it is a recovery partition, Windows can probably reuse the one that's already on the drive

On another note if you do reformat it (if it lets you), it will cease to function like it should

my samsung notebook had such a partition.
it contained a so called "recovery system" that could make a image of my system to another partition.
also wasted like 20gb of my precious space.

but there was no magically unremovable thing to it.
i could remove it with the usual windows tools :)