Then remove the IM Shield completely if you don’t run IM applications at all (like me).
From the windows Add Remove programs, select ‘avast! Anti-Virus,’ click the Change/Remove button and from the next window select Change, take care and uncheck the box to the left of the IM Shield (not essential shields) and OK your way out. That also has the added advantage it doesn’t leave you with an Exclamation ! mark in a triangle over the avast icon, and it is permanent unless you reverse the action.