Hello matttttttttttt and welcome to the forum.
Do you have anything in your Avast Virus Chest? If so, please give a screen shot (preferably) or type exactly what is in the Chest.
Next, 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 OTL logs (save them as
ANSI and not Unicode). When the OTL scan completes, it will open two notepad windows. OTL.Txt and Extras.Txt. Post the two (2) OTL log as an
attachment (Additional Options > Attach > Browse (the logs will be on your desktop > Post).
I am going to refer you to our Certified Malware expert, named Essexboy. He will also review your logs and give you further instructions, however he comes on the forum late UK time. He will respond to you in this thread, so remember to check this thread daily.
Please do not make any further changes to your machine once you have provided the logs. Thank you.