HTML:Iframe-inf, found in Quick + Boot-time but not Full scan

Hi all am i infected?? my internet is running like a dog and my Quick scan and Boot-time scan finds the Iframe-inf infection but a Full system scan doesnt find anything.
I’m a touch confused.
any help would be great.

P.S love avast and recomend to all.

have found and moved to chest…if it was moved to chest then there is nothing more to detect
…or do you mean find it every time you scan ?