XP Defender

My son is using the free avast software on his vaio. His OS is XP. He recently was hit with the “XP Defender” and it has pretty much made his laptop unusable. Has anyone here been hit with that particular program and found a way to get rid of it? He has tried several suggestions but so far nothing has made any difference!

Please attach your logs. (AdwCleaner, MBAM, OTL and aswMBR…!!)
Instructions: http://forum.avast.com/index.php?topic=53253.0