virus? or crazy?

For future reference this trojan is indeed a genuine backdoor but it's not all that common in the US but is common in Europe and Asia. It tends to be detected as a variant of Klez by other antiviruses unless it has already successfully disabled the AV. If using Avast you have an option of scheduling a scan on reboot which will allow you to remove any virus unless it's embedded in an compressed archive.

This bug spreads through the file sharing networks and usually comes embedded in archived files which is how it bypasses your AV untill you have it set to scan compressed files also.