RE: Avast false positive windows xp sp3 file 'sfloppy.sys'
Files that are detected when doing a scan or navigating the system should never be deleted before confirming that indeed the detection is really malicious. When I used real time AV, the first setting that I changed was the one that gave me option on what to do if something gets detected. I would never use an AV that automatically deletes files, nobody should . The user should have the option of sending the file to quarantine or the virus chest if ignore is not an option. Personally, I would not even send files to quarantine neither, unless I was certain that the file is malicious.
As of late (2 years), Avast has been doing this kind of thing a little too often, they fix it quickly but they should be more careful about system files, in my opinion. Most false positives are no big deal but system files can render a machine useless and not able to reboot.
Bo