I have run SFC /SCANNOW on my Vista notebook. SFC identified server files that it said were also damaged in the backup location. The log in \windows\logs\cbs\cbs.log identifies all the problem files - where do I get the replacement files given all the service packs, hotfixes and automatic updates applied to my machine ? is there a definative source for these items?
I think the best way out is to repair the OS with the Windows CD (even if its the option you are trying to avoid), download the latest SP (for Vista its SP2) apply it & let auto update do the rest.
The problem is that as you said, the file sources are varied (like RTM OS, SPs, auto updates, hotfixes). So finding the right, untampered, legit version would be too tedious.