Problem with Avast

I too installed Comodo Firewall with Avast and Vista Ultimate. I have uninstalled Comodo and also the Comodo malware program. They still appear to be working on my computer. How do I remove them completely? I also have a problem with asterisks appearing when I am trying to type and I have to keep ahead of the asterisks in order to achieve anything.

Any suggestions welcome. I am going mad