Blinking Finder

No matter the program I'm in, rapid typing can stop action & bring up a 'page info' window. The Finder may also suddenly 'blink' & reappear. This happens often! I've run Disk Warrior, TTP, Preferential Treatment & trashed bad prefs, restarted. Same problem returns. Help, please.

disable stuffit avr in system preferences

Thanks you, I'll sure do it!