Hi Guys,
Yeah I know Vista is not much good so I may have to bite the bullet and upgrade to W7.
Martin
I have WinXP, Win7 and win10 systems and I don't see this kind of disk activity.
What I find strange is that the avastUI.exe runs the avast User Interface and essentially that doesn't have a scanning function, whilst it may have access to your HDD. The AvastSvc.exe is the main controller for the scanning engines/shields.
What column name are you viewing to see this activity ?