Should you get a clean result back or unable to do anything after doing the boot scan or the MBAM scan, please check the information on the first post of this thread under Virus/Worms for you to check your machine for malware: http://forum.avast.com/index.php?topic=53253.0.
Follow the directions for obtaining the OTS logs (save it [u]as ANSI and not Unicode). Post the OTS log as an attachment (Additional Options > Attach > Post).
Please do not make any further changes to your machine after you have provided the logs.
IMPORTANT: If you are on a home network, disconnect the affected machine from the network. Do not share a USB/flash drive with this affected machine. Do not use this machine unless instructed to do malware removal; use a different machine to check email, sync your phone, etc. if possible. Depending on your logs, we may need to refer you to our Certified Malware Expert.