Can I clean my computer completely after my email has been hacked?
How do you know your email has been hacked?
Let’s find out if you are infected first before doing anything drastic.
Have you scanned with avast?
Have you scanned with MalwareBytes?
If you are not infected there is no reason to clean/reformat your machine.
If you are infected follow the directions here http://forum.avast.com/index.php?action=post;topic=115901.0;last_msg=900574
Be patient one of our malware removal experts will come along to assist you.
You might want to start a thread in the viruses and worms section if you are infected. http://forum.avast.com/index.php?board=4.0 