windows 7 - partition managing not allowing to expand

I wanted to dual boot Linux + win7. I got to the disk management program and discovered that I can not extend the win7 partition.

(superuser also wont allow me to post images so I cant stick an image here)
The image basically says there is an OEM partition
then there is 20GB of unallocated space
then there is the win7 partition filling the rest of the hard drive.

I found out I need to delete the windows partition in order to extend it if its not directly to the right of the partition i want to extend.
and doing that...well...will delete my windows.
I want to get the unallocated space into the win7 partition and then shrink it into a win7 partition and a Linux partition.

Answer

Sounds like you have room on the left of the partition you want to extend, and no room on the right. You can move a partition to the left and then extend it to the right. Windows may do that, if not then Easeus partition manager(which is free) or others e.g. paragon partition manager(also free version).

You should use specific terminology when talking about something as significant as partitions. When you say OEM partition before the windows 7 partition.

Perhaps you mean a Partition of 100MB Windows describes as "System Reserved"

If so, I don't know how you ended up with a space between it and your main partition. So I wonder if perhaps you don't mean that

But if you backed things up you're free to experiment. Try moving the partition you want to extend to the right, try moving that partition to the left first, then you'll have space on the right extend it.

And to be clear, (and particularly when you don't have a pic), write the title of the window you're working in to partition the drive(so that it's clearer what screen you're looking at) e.g. The Windows 7 "disk management" window