A normal boot results in a screen threatening all kinds of stuff if I don't pay - blaa blaa and a locked up machine.
Safe mode boots the same as does safe mode with network support.
Safe mode with command prompt lets me in and I can run regedit from the command prompt.
Google advice points to registry entry WINLOGON and tells me to delete value and insert explorer.exe.
explorer.exe is already the value - what to do now be the cry.
Machine will not boot from Flash Drive - I think that is the age of the machine.