What is OEM Partition?
When you buy a brand computer, such as Lenovo, Dell, HP...rather than a DIY one. The
Original Equipment Manufacturers (OEMs) will contain a system recovery partition on
the computer hard drive. This partition usually includes a digital copy of the
Windows installation file in case of emergencies.
(Figure 1)The special partition, normally hidden, can have a size of from few MB to 10 GB or
more. Generally speaking, OEM partition is not very useful to us. If we reinstall
the operating system in future, the OEM partition is more useless. So we said the
OEM partition can completely be removed if you are not a computer newbie. However,
in some OEM system, such as those from IBM/Lenovo, is impossible to delete within
Windows.
How to Remove OEM Partition?
Now we concern how to remove OEM partition.
The first method:
By using advanced Diskpart, a text-mode command line tool interpreter which enables
storage objects such as disks, partitions or volumes configuration and management
from a script, remote session, or direct input from a command prompt. (free download for XP, 2000, and 2003).
Steps:
1.Open a command prompt as administrator.
2.Run Diskpart application by typing Diskpart in the command prompt.
3.Type “list disk”. This will show all the disks.

We know from the Figure 1 that the OEM partition is located on Disk 2.
So we type “select disk 2” and press Enter key.

Type “list partition” to list all the partitions on the disk.

Now we can see the OEM partition is Partition 1. So type the command “select
partition 1”.
Then type “delete partition override” and press Enter key.

Thus, we have removed the OEM partition successfully.
Is there any easier way? Yes!
The second method:
By using third-party partition management software-AOMEI Partition Assistant. We are
able to spend less time and fewer steps to remove OEM partition.
Download AOMEI Partition Assistant
Standard Edition, install and run. The OEM Partition can be seen from the main
interface. Right click and select “Delete Partition”. The pop-up window like the
below picture.

Randomly choose one and click “OK”. Back to main console, click “Apply” to commit the
operation.

Once the partition has been deleted, we can also use AOMEI Partition Assistant create a new partitionwith this space, or simply mergeit to existing partition by extending the size of the existing partition.
More information please visit Online learn
User Manual.