My Acer Veriton M290 randomly goes into "critical" mode and starts flashing error messages, i.e. "itunes library not saved, not enough disk space". "cannot open task manager, close some programs and try again" (and there will be no programs running). "windows update is not set up, go to action center to set up". When I try to go to Control Panel, I get - "too many programs running, close some programs and try again" or it just turns itself off. When I turn it back on again, everything will be back to normal, for a couple of days anyway. i am not computer savvy at all and use my computer for emails, itunes and my daughter uses it for her SIMS. What am I doing to upset my computer?