That sounds more like a permission issue of some type, or a corrupt OS. Though I suppose if Avast were going through its first system-wide scan on a slow computer, it could make programs appear not to load (they would load, just take minutes to start). However, if Avast was installed on Monday and this started on Thursday, I'd be more inclined to blame the IT contractors' changes.

As far as examining the logs -- why try to place blame on anybody? Fix the problem, consider it an act of G-d, and move on. If HR is actually spending time on a witch-hunt, the HR people should be subject to defenestration. "Writing a report" because of a Windows machine going t1ts-up *sigh* what is this world coming to.

I suppose one could examine the Event Logs for any application errors (and system logs for any disk i/o errors), but this should be an avenue to fixing the problem, not an avenue for finding whom to string up, unless this is a recurring problem with the IT contractors or a given employee. Lastly, was Symantec cleanly removed before Avast was installed?