1) On a separate Mac computer, log into the Mac App Store and download the latest "Install macOS" app.

2) Take a USB with at least 8gb of space available on it and insert it into the Mac used in Step (1).

3) Hold "Command" and press the "Space Bar" to open the Spotlight Search shortcut and type "Terminal.app" (without quotes) and press "Enter" to open a Terminal command prompt.

4) Repeat Step (3) and open the Spotlight Search Bar again, except this time type "Disk Utility.app" (without quotes) and press "Enter" to open a Disk Utility window.

5) In the Disk Utility window, on the left side panel, you will find a list of any disks found on the computer (this includes the internal Hard Drive and the USB inserted in Step (2)). Click on the USB to highlight it, and then look at the bottom half of the Disk Utility window and you'll see all details about the USB device. Look for an entry that gives the device disk number - you can identify this by the entry that looks like "/device/disk#" (where the # is a number specific to your device). Write down this disk number to use with the next step.

6) Open a Finder window to the Applications folder where you'll find the app downloaded in Step (1). Right-click the app and choose "Show Package Contents". Double click the "Contents" folder that appears, then open the "Resources" folder that appears.

7) Bring up the Terminal window opened in Step (3), and type "cd" then hit the Space Bar, then click+drag the Blue folder icon at the top bar of the Resources folder and drag it into the Terminal window then hit enter. This will change the Terminal into the same directory as the Finder window.

8) Now type the following command in the Terminal window:

sudo ./createinstallmedia --volume /Volumes/[Enter Name of USB device here

This will create a USB disk that will reinstall MacOS when used.

9) Insert the USB disk into the Mac that is having the IBM issues and hold the Alt key while powering on and choose the USB device you just created.

10) Wipe the disk using Disk utility, then complete a reinstallation of macOS.

11) Before starting the Mac, perform the steps contained in the previous pastebin just for good measure.

12) Complete the initial setup of the Mac without connecting to the internet until after it has finished completely.