maybe you wont find it at all. there is a posibility that the previous authors of the logos started from one (the same) font and then added their creativity.
that will differ from author and inspiration/creativity so you will have easier
(in this case) or harder task of recreating them.
Delete the icon cache X:\Documents and Settings\XXX\Local Settings\Application Data (it will rebuild upon restart)
Restore the dll (with the system icons) %SystemRoot%\system32\SHELL32.dll with a good one (from winxp cd)
and maybe try tweakui - rebuild icons
thats all i can...