It sounds like the "Spyware Protection" scam.
As far as I know, this program sneeks in via bona fide web sites that have been compromised, and instals itself under the guise of a Windows Update.
Or it might have been a site called "OverFlowingBoobs.com" (or not if it was your mrs that was using it at the time!)
It stops you opening any form of repair or defence, and is particularly sticky, and good at hiding itself.
Even Task Manager is blocked so that you cannot switch off the process even if you could identify it?
Start up in safe mode by pressing F8 or F12 before Windows launches.
Select
Safe mode with network support.If you don't have it already, download Spybot Seek And Destroy, and install it - with updates.
Run Spybot - and while it runs, search for a file called "Defender.exe" and rename it - something like "Deceiver.txt"!
(right click on the search result, etc. etc - not sure if your gran knows how to suck eggs!)
When Spybot has finished scanning, it should show the threats highlighted.
Click "Fix Problems" and then re-start the PC.
For future peace of mind;
Go to "add and remove programs" and TRASH
Windows Defender -
Microsoft's malicious software removal tool, as it is useless, apart from taking up bandwidth updating itself!
Use SpyBot which Microsoft used to recommend before they developed their own ineffective product, AND MAKE SURE YOU UPDATE IT REGULARLY.
You can use the Task Scheduler if the PC is always on at certain times of day/night.
Hope it IS just the spyware, and that the fix works for you - it seems to depend on the way the PC is set up apparently.