Alerts on what, a file on your system or the site you are trying to register at ?
Can you be a little more detailed on what it is you are doing ?
What is the malware name, the infected file name or URL, where was it found e.g. (malware name, C:\windows\system32\infected-file-name.xxx or URL) ?
Check the avast! Log Viewer (right click the avast 'a' icon), Warning section, this contains information on all avast detections.