First - I have gone through as many possible solutions I've found here and elsewhere.

[Edit - to describe the issue in more detail, the PC appears to boot correctly, but instead of the logon screen, I have been getting a black screen WITH the pointer cursor, and it responds correctly to the mouse. Pressing CTL-ALT-DEL brings up the logon screen's background, but with no logon area nor any other content. This screen was at the full resolution before I uninstalled the graphics driver in safe-mode.]

I also just ran a full up-to-date AVG scan from boot media.

[Edit - the AVG scan, which was updated to today's virus signatures, found no issues at all.]

So - steps I've tried:

1. Safe Boot, Restore from before the issue - done, no help.
2. Uninstall the graphics driver - done, now i have a 1024x768 fallback screen, still no way in.
3. sfc /scannow - only doable from Safe boot obviously, but no change.
4. [Edit - booting from restore media, performing a startup repair and...]Restore further back - restored to 2 days ago, and I'd had many reboots since then with no problem.
5. Enable autologin to try to get beyond the login screen - done, doesn't work.

It seems the best advice is complete reinstall, but I really don't want to do that because it'll take 3-4 days to add all the apps I use.

Some key points to note - in both states - before and after removing the video driver, I always had a mouse cursor on the screen. CTL-ALT-DEL flashes up the login background, but no login info.

I can (and often do) reinstall from scratch, but was at a fairly stable state before this, and would prefer not to.

-Paul