I haven't had an anti virus s/w on my iMAC for a while. I recently installed Avast and ran a scan. It came up with a dozen viruses/trojans (e.g., rpcinstall_us.dll). When I tried to repair, delete, or send to Virus Chest, it complained that 2 of them do not allow that and the others were unsuccessful.
I also have a ton of "err 13" items in my scan result, and I'm not sure what they mean.
Any and all help will be most appreciated.