When registering a new device (my Dell PC desktop) I am required to enter the serial number. There is no serial number on the pc but there is a service tag number, which, Dell tells me is the same thing. But the Microsoft page wont accept it. What to do now? By the way, this same device was registered in Microsoft 365 before but I removed it while I worked on it. (Replaced HDD with SSD). I cant rememeber how I got it registered before,
