Vista - 'Protect' folder

I was having issues regarding repeated username & password prompts on Windows
Mail and so followed the advise from a previous thread (that I can't find
now) that suggested copying then deleting the 'Protect' file somewhere within
C:\users\*username* etc.. I have done this and now need to replace the file
but cannot remember where it went.

Can anyone please advise as this is now affecting access to the rest of my
email a/c's that I previously had no issues with.

If it helps - the sub folders within the 'Protect' folder begin: S-1-5-21-
and continue with more numbers.

Many thanks