How to solve "The specified service has been marked for deletion" error

There may be several causes which lead to the service being stuck in 「marked for deletion」.

1. Microsoft Management Console (MMC) is opened. To ensure all instances are closed, run taskkill /F /IM mmc.exe.

2. Services console is opened. This is the same as the previous point, since Services console is hosted by MMC.

3. Event Viewer is opened. Again, this is the same as the first point.

4. The key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\ exists.

5. SysInternals' Process Explorer is opened. Closing it should lead to automatic removal of the service.

6. Task Manager is opened.