Hi so you are still getting the Win 32 backdoor meeage?
You can run MBAM with your antivirus as it is an antimalware not A/v application.
When do we know......??
Quarantine plays a nice middle ground, because it moves the file to safe storage under control of the antivirus program - so it can't harm your system - but it's there in case a mistake was made and you need to restore that file. So if after several days the PC is still operating normallyy then it would OK
After a scan...
Only choose 'delete' if (a) the antivirus scanner specifically recommends it, or (
you're absolute certain that it's not a legitimate file