I only did this as an exercise, well that and because I paid for it so I will kn well use it :-)
a full image copy and ditch A8 would have been simpler.
Thanks to the person that gave a link for avast 7 free. I appreciate the effort.
I was hoping for some buried link from avast itself.
see (*) for the point of the ramble
System restore wouldn't work, safemode wouldn't work, lastknowngood wouldn't work.
A recovery console chkdsk sometimes let it boot to windows safemode but it was fragile.
Using recovery console and patching the restore points
I finally found one that would allow a full restore. System restore wouldn't even run on most.
then stopped every likely looking service in recovery console
booted and uninstalled avast 8 and the components it had installed
tested and backed up system
... several iterations of crash/rebuild later ( so the sequence may be a little hazy)
avast 7 free didn't seem to have a problem
(*)
reinstalled avast 8 free with the software update component turned off
- not the avast update but the thing that tries to update other software
- it seemed to start crash when it tried to do those updates
seemed okay, with or without zonealarm
loaded license for pro
it updated to pro, again seemed okay with or without ZA
I suspect something in those updates it applies after rather than A8 itself but thats a guess.
For now Avast8 Pro seems to be behaving but ZA is dead anyway, too much bloatware is becoming annoying on older computers. Particularly if the bloatware then does even more updates.
It would be nice if an update had some sort of benchmark indication of system impact before installing.
