I don't know how it's done in Windows, but on the Mac side of things, when a company provides a computer to an employee, the IT department will usually put some kind of proprietary software on it (on the Mac side it's called "MDM") that can over-ride the employee's attempts to "wipe it clean". This is in the firmware, not "on the hard drive", so it can't be "removed" by changing drives.
The only way to "get full control back" is to have the MDM software removed, almost always by the IT department that installed it. There are ways around this, but they're tricky and not approved by Apple. Generally, Apple will refuse to remove such software unless the owner can provide proof of initial ownership (sales receipt, etc.).
I'll guess that almost certainly there is similar software on the PC/Windows side of things.
I'll also guess that there are more tricks and workarounds to overcome it on the PC side, too. But although I could solve almost any problem a Mac user here has, I know nothing of PC's.
