panther, if you only downloaded the zipped file that was attached to an email, and then you unzipped the zipped file, which, i suppose, contained a malicious “EXE” file, but you didn’t actually excecute the malcious EXE file, maybe because the “avast” program flagged it before you had a chance to execute it, then, in that case, i don’t think the malicious file managed to do any harm since it was never executed…
occasionally i download malicous files, for one reason or another… just because i download a malicous file, that doesn’t mean that my computer is infected with malware… as long as i don’t execute the malicious file, it doesn’t do any harm to my computer…
so, the question is, after you unzipped the zipped file, did you execute that malicious EXE file that it contained? if not, then i don’t think that it did any harm to your computer…
regarding the “CALMAIN.exe” file that was flagged, if it was part of “canon” software that was installed on your computer, i would suspect that it was a “false positive” that didn’t have anything to do with the malicious file that you downloaded…
if i am missing something, like, maybe, if, with your email, you can just click on a zipped email-attachment and it is automatically extracted, and the file within the zipped file is then automatically executed, after having been extracted…
if you actually executed the malicious EXE file that was contained with the zipped file that was attached to an email, i think you should assume that your computer was infected with malware and take measures to make sure that the malware is removed, like by following the instructions to run a scan with “adwcleaner”, malwarebytes, OTL etc, posting the scan-logs and then letting one of the “experts” look at the logs etc etc…
p.s. regarding being stupid, i think that virtually all of us occasionally do “stupid” things, with our computers… one thing that i rememeber…one time, i came very close to logging into a fake yahoo webpage that was used for “phishing”… if i hadn’t heard someone say “that’s a phishing webpage!”, i would have logged into it…