Thanks Jack. All fine in Device manager. Tony

Thanks Jack. Yes, the HP Officejet 8010 series is listed with the words 'Driver unavailable'. HP's support WhatsApp team have done sterling work trying all the normal things and have had to give up, saying it must be a problem with the Acer laptop. That is now quiet old, hence asking the community! Ihave just used IOBit Drive Booster to update any out-of-date drivers, but that also hasn't solved the problem. Back in June the Windows update stopped loads of printers working- 4 that I dealt with - so I'm wondering if the issue might be another Windows update, but can't find anything.

Thanks again so much for your time Jack. As usually happens with me, by the time I found it wasn't working (we rarely print from the laptop) there were no Restore points! I tried uninstalling the two known Update culprits, but this time it didn't restore the printer. So I reinstalled Windows 10. It automatically updated it self of course, and again I had the 'Driver unavailable' in Settings.

Thanks Jack. I've done that (quite a few times!) and HP support have also done it several times, including after various different and increasingly thorough uninstalls of the HP software and driver. Tony

Thanks Jack. That's part of the problem, as the normal Officejet entries under Printers and Print Queues aren't there. When I run the installer (OJ8010_Full_WebPack_49.3.4475.exe) it fails to connect to the printer, even being given the 192.168.1.6 address manually. 

Thanks Jack. I did as you said, turning everything off and then restarting all in the order you said. On the printer's screen the IP address is 192.168.1.6. I then logged into the Router (192.168.1.1) via a browser and entered the admin user name and password from the back of the router. That confirmed the printer's IP address is definitely that one.
I reinstalled the printer software again and tried to connect. It didn't find the printer until I gave it the IP address manually. 1 tried 192.168.1.1 then 192.168.1.2 up to 6 (we have the TV, PC, laptop and 2 android phones connected.) Using 192.168.1.6 it started the 'HO Device Setup Process' with '1....2....3...' on the screen. It tried for a few minutes then said 'Unable to connect. Connection to internet failed or not found'. It was definitely connected as I checked web pages loaded. It then said 'Setup complete'. In Settings there is the printer, but 'Manage' only accesses scan options and in Word there is no printer installed. When I tried to add a printer from within Word, it came up with the error 'Find in the directory. The Active Directory Domain Services is currently unavailable'. I checked and it isn't listed in Service.
Iran HP Print and Scan Doctor 5.5 once again and it said it had fixed the printing, but still only the scan options available in Setting and no printer installed. I tried to remove the printer in Settings but it won't remove!
I tried stopping AVG internet Security and to connect. Still no good.

Afternoon Jack. Thanks again for your help. Well, I ran a full scan with AVG which found nothing and also installed and ran Malwarebytes to double-check. It found 16 PUPs which I quarantined, though I don't think they were significant. There were no printers listed in Device Manager and nothing under Print queues except the root. I tried to add a printer again and failed. So I totally uninstalled AVY Internet Security and Malwarebytes. After rebooting, I again tried to add a printer and failed. I then tried to add a local or network printer with manual settings. I tried 192.168.1.6 and all ports options (same plus 192.168.1.6_1 as well as _2 and _3. Every time, it came up with the option to install the Officejet 8010 series and every time if gave the error that it couldn't find the file. I also tried creating new ports with the _4, _5. _6 & even _7. Same thing- it found the right printer but couldn't install the driver as it 'couldn't find the specified file'. I tried the option to install from a disk, but it wanted a .inf file for the OJ8100 and it didn't exist on the computer anywhere, so that also didn't work! However, I noticed that as well as the OJ8010 it also had my previous printer, an OJ 8620 listed. Years ago I solved an HP printer problem by telling Windows it had a different model of printer connected. So, kind of in desperation, I installed the Officejet 8620. Would you believe it, it actually installed and printed a test page! I then went into Word and printed to the ""Officejet 8620" a complex document in Bookfold and it printed it perfectly as a booklet.
So, Jack, the problem is, to all intense and purposes, solved!
My wife is thrilled. I've still got no idea what the problem is with the OJ8010 driver, but we are going to take that as a win!!
Very many thanks for all you help and advice. Tony