My brother-in-law recently gave me a PC from his business that had been used by a former employee. Works well but the only problem is that as it is away from "its domain", I cannot do any updates.
The last Windows update was August last year and although it says that there are security updates ready to download and install, all I get is "Download error 0x80d05001."
As usual, the "Internet" is very vague about what this error means.

Any help will be very much appreciated.
Cheers.