Serial number of self-built PC

joeandmarg0 said:

In either Powershell or Command,type in---slmgr /dlv---and see what numbers are given and if any are of use..

This yields information on the Windows license, but not on the device itself. As I build my computers myself, there simply isn't such thing as a "serial number". I have never tried to install the Flight Simulator, nor have I tried to "register" my computer with Microsoft, but it seems to me that given the variety of hardware vendors, there is no way even Microsoft can tell which number is a valid serial number and which is not. I suppose the problem is with something else. My advice would be to simply call Microsoft and find out how to download the product that you've purchased.

Sorry for any confusion. I have a self built PC I'm using here, now. I have an Acer laptop. Both of these are registered in my MS Account. This one has "System Serial Number" as the entry in the Serial Number field. The laptop has an Acer s/n in its s/n field.
I have built up a computer for FlightSim2020. I cannot add it to MS Account as Bill wants a serial number. I typed System Serial Number -nope. I've since tried strings of characters found in BIOS, Mobo, Device ID and a Product ID. All no use.
So I cannot download the sim. I am going to try for a refund. Wasted too much time on this. I'll try to get it downloaded from Steam.
I'm grateful for all your feedback. I'm sorry to have wasted your time as well.

FS2020 Download-Installation-guides

I wish I'd seen that earlier Megahertz. In the meantime I've got a refund and took a look at Steam. Way too complex for me and lots of neg reviews re Support. At least I got responses from MS. I've ordered the DVD boxed version. I suspect I shall be reading your Link in earnest for FS2020 update downloads. Hoops and hurdles...
Should I mark this as "Solved"?

Yes, please mark this as solved