I did this and now I get 2 infections instead of 1.
What do you mean, you have 2 infections? Did you check if sfloppy.sys is really gone from system32\drivers directory (hope you are not checking just system32 directory, as
available implied earlier
?
If sfloppy.sys file is really deleted from the system32\drivers directory, doing what I mentioned earlier, will just place a copy of this file (the file from sp3.cab should be the same as the original one in system32\drivers) in system32\drivers. If the file is there, you should be asked to replace it.
PS: I restarted the system a few times and everytime after Windows started, Avast showed the same warning about sfloppy.sys. Checked manually for updates and the virus definitions updated from Current Version: 111206-0 to 111206-1. Rebooted again and the problem is still there, so as others suggested, I just ignored it and now am waiting for a new update, that will hopefully fix that.