Congratulations You Won! (virus or not?)

Okay, I know this is my third post but can you please help. so i’m pretty sure it’s a virus but I keep hearing " Congratulations you won!" And it’s irritating me, people tell me to download Malaware Bytes and I’m not sure to trust it or not. Can someone please help. Obviously Avast isn’t finding it because i’ve done a lot of scans.

Yes you can trust Malwarebytes see my signatur

but why start a new topic, you already have one ? http://forum.avast.com/index.php?topic=61351.0