Just as a follow-up from the previous post, Symantec have released the removal instructions for W32.Downadup.C
You can find them here
The removal instructions are part automated using the Antivirus software, but also require the editing of the PC’s registry and the usual system restore issues.
It is the registry edits that mean these instructions are beyond a large number of users. (and potentially fatal for the PC)
Whether they will create a removal tool that makes the process much easier I don’t know. (I havent searched for any other instructions, if you know of any post them here)