That many of today's malware, virus, trojan (call them what you will) are now booby trapped. So even if you use an bootable Live Antivirus it may blow up on the next boot.
What this means is such work is now more expensive if the client is not ready for a wipe out. You clone the drive for safety then use a current Live CD (definitions are updated and a new CD issued, not just definitions.)
I think you are trying to run Windows and scan those drives. Given the changes in PCs over the years I think you'll have to use new ways.
I have in the past used one computer with different Virus scanners.
I would simply plug it in using a sata or usb to hook to the computer which would be used to scan for virus or malware or rootkit. I tried using administrative tools- computer management to make the drive readable. The problem with this when you do this it will no longer work on the original computer it came out of.
Does anyone have a solution which won't mess up drives. The good virus scanners will not work together without messing up each other. Is there a way to take definitions to a live cd?

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