You can't upgrade windows 10 64 bit on windows 8.1 32 bit system.
If you have another pc, take out the harddrive from the one you got problem. put in usb docking system attach to another PC.
right click command prompt run with admin right.
List disk enter
select the usb disk with number enter
and then unattached the usb disk
put it back to the one you want install windows 10.
try new install windows 10 and kms activation with admin right online again.