ok, sometimes I'm not sure where to post my questions. Thanks for correcting me. I have Lenovo 515 , using windows 8.
it seems Avast has changed somethings on my pc. My Lenovo app icon is on the task bar, but don't always appear on the desktop as they did before. Sometimes when booting up, I have to sign in , other times the desktop icons appear as usual. Maybe this makes little sense as explained, but think i'll uninstall Avast ; maybe just use Charter ant-virus.
Thanks everyone !