hi, janj, great stuff and thanks for returning with your fix, and for the pat . You don't have that trojan problem referred to in that link you mention in your first post - you had a real break in the software [the trojan puts up a false warning, breaks your desktop to scare you, and then sells antispyware - pretty much the sys keeps working. Well, it has to so it can sell stuff..].
Bit of sfc background :
[sfc checks protected files being used by the sys for any overwriting; if it detects that it copies in new files from the dllcache; if the dllcache has corrupted files it asks for the CD.... but it beats me why the cache gets corrupted - i always have to load the CD...]
KeithMcL commented: Some love for helping me ;-) +3