NAV Behaving Erratically

I am using OS 10.5.8 with NAV 11.1.

 

There are three problems....

 

LiveUpdate now occurs every time I log onto the computer.

Previously it occured only as scheduled.

 

A full virus scan recently started unrequested.

Previously it occured only as scheduled.

 

The lock to prevent changes without password won't stay locked.

The lock has been acting flaky for  while.

 

Any thoughts?