The virus we have isn't a new one: it's been knocking around in some form or another for a couple of years. Every now and then it causes a fresh bout of infections, usually caught from perfectly legitimate and innocent sites. Usually those businesses sort themselves out quickly (as did the site I caught it from), so no names, no packdrill. It's is known under many names, most of which include the word "ukash" - the system by which you pay to supposedly sort out the problem.
The first thing you see when the virus hits is a variation of the following screen - there are French, Italian, German, Spanish, and a couple of UK ones (at least).
What we had on our monitor.
One of the UK variantsOnce the virus is there, it is very difficult to do anything at all with the computer - the screen image continually reappears, and it corrupts your explorer file (the one you use for navigating windows) so that "ctrl-alt-del" doesn't work either.
I restarted the computer in safe mode, which at least gave me access to some of the computer's functions - I ran a couple of antivirus programs, including Malawarebytes, SUPERantiSpyware and AVG, all of which found infections, but didn't manage to sort it out. I also followed some of the manual removal advice found on various pages to no avail.
In the end I have posted to a really good forum - bleepingcomputer.com, and last evening received advice which I will start following some time today when I feel stronger. The great thing about the forum is that one tested expert gives you advice on your problem rather than getting a dozen different opinions, and the process is followed up with repeated tests of your system until all problems are definitely sorted. This may be a long and precise process which requires plenty of patience and brainpower, so starting it at night may not be the cleverest.
In the meantime, we are using our netbook (as mentioned here), but connected to the main monitor (I deliberately bought a netbook with an external monitor connection) and an Apple USB keyboard and mouse. I am also running it on LAN (wired) networking, which is so much faster than the wi-fi. So far this setup has been so good that when we have to replace our computers I am tempted to buy another netbook and run it like this as our main machine. It is certainly no slower than the Dell I am usually using, and having no fan it is amazingly silent. As I am fairly good about backing our information up, everything we need to continue operations we can continue doing: we have up to 5 copies on data on different hard drives, depending on how important it is.
So - plenty of coffee and a steady hand, I'm going in. Wish me luck...
Edit - 1st step of the devirusing proceedure done, so far so good,. Judging by how long this one seems to take to conquer, it could yet be some time!