For system recovery or factory restore OEM partition is used, which helps to restore data easily and quickly. If you are selling your computer, just deleting files or formatting is not enough to ensure your privacy because OEM makes data recovery fast.
To delete OEM partition with Diskpart: enter diskpart>type list disk>type select disk n>type list partition>type select partition n>type delete partition override>type exit. 
Formatting a hard drive is the process of preparing a data storage device on the drive to be used by an operating system by deleting unnecessary drive or all of the data to the setup file system. The file system used in windows is NTFS and Fat32. There is various formatting process to format partition; Disk Management tool is usually used to format windows. You can also use formatting commands or free formatting software tools.
What to do Before Formatting a Hard Drive?
- Download and install software tools to format if you choose to format using formatting software on your own risk, which is easy to use and effective.
- Make sure your battery is full and well connected to power if you are formatting a laptop.
- Remember to save your serial number because while formatting, your application will be lost, so you need to reinstall them.
- You should keep backup of drivers that require after the format, or you can download the latest drivers from the official website.
- If you need any data, file, and information, then backup relevant data first.
2 Methods to Format Your Hard Drive
Once you think you are ready to start formatting your hard drive, I will teach you what to do further; there are three methods to format your hard drive including OEM, follow the following steps mentioned below:
How to Format OEM Partition Using DiskPart? (Method 1)
Diskpart in the computer is a command-line disk partitioning utility of the operating system. If you are formatting your window using disk part, follow the following steps:
Step1: Open Run box
To open run box press windows key + R to open run dialogue box.
Step2: Enter disk part in the run box
After you open the run box, enter the disk part in the run box and click OK to open the command prompt window.
Step3: Type list disk
Type ‘list disk’ in command prompt to display all the disks available on your computer.
Step4: Type select disk n
Type ‘select disk n’ to identify which disk you want to delete.
Step5: Type list partition
After you select the disk, you want to work with type ‘list partition’ to display all the volumes available on the hard drive.
Step6: Type select partition n
Here n stands for the volume letter on the hard drive. Type ‘select partition’ n to identify which partition you are going to work with and remove.
Step7: Type delete partition override
Finally, to remove the OEM partition Type, ‘delete partition override.’
Step8: Type exit
After following all 7steps, you will get a message “DiskPart successfully deleted the selected partition” finally type ‘exit’ to close the windows.
How to Format the Hard Drive Using Disk Management? (Method 2)
Disk Management is an implementation of a logical volume manager in the operating system. If you are formatting your window using Disk Management, follow the following steps:
Step1: Click the start menu
You can see the start menu in the display of your window, with a window icon.
Step2: Search Disk Management
Go to start menu and search disk management.
Step3: Click Disk Management
After you search disk management, the search result will appear click disk management; then, you can see all the disks and partition on the pop-up window.
Step4: Locate and right-click
In a new pop-up message, you can see all disks and partitions. Locate the disk and partition you want to work with and right-click on the partition you want to delete.
Step5: Select Delete Volume
After you locate and right-click on the partition, select ‘Delete Volume’ from the context menu, which appears in your window.
Step6: Click Yes on the Delete simple volume
After you select to delete the volume, click yes on the ‘Delete simple volume,’ which prompts deleting this volume will erase all the data in the partition. So, you should keep the backup of any data you want to keep and are essential for the future.
Now, if you want to completely format a hard drive including OEM then you can use any method mentioned above. But don’t forget to read what you should do before formatting a hard drive because you should note those things before formatting a hard drive.
If you face any problem while formatting hard drive or if you have any questions regarding this article on How to completely format a hard drive, including OEM then you can comment in the comment section below or you can visit our official website Online Help Guide.