Have since found that by removing the wireless internet dongle, the problem has, for now, gone away..... Have connected it to the net on a home network and all working OK. Seems must have an issue with the internet dongle. Any ideas why this would happen. This is NOT my computer and I'm trying to sort the problems for someone else. Seems the computer was working fine with the dongle and then went bad.
The Legend of Zelda Breath of the Wild review: Five hours with Zelda on the Nintendo Switch