Full system scan stops - solved

I can’t seem to run a full scan (only a quick scan) I am running windows 7.
Full scan doesn’t get past 0% and stops at different folders each time I try to run the full scan
How do I get full scan to work again?

I ran an update to Avast and restarted computer - and the full scan runs fine.

What OS/SP ?
What exact version of avast ?
Any other security (related) software installed ? (or was there)

C:Windows\system32\WUDFRd is no a file but a folder.

Windows 7 Pro

Avast Internet Security

I have no other security related software installed - never had

I have Piriform CC cleaner… that’s as close as something security related