I'm trying to get a lookup type function that will pull information from two
different files into a third that I am working in. File1 is a list of part
numbers with two columns. Column A is a part number that is assigned for use
in external communications. Cloumn B is a part number that is assigned for
internal use. The next set of files are the individual parts files. There are
columns for Weight, Lenght, Cost, etc. Each separate file is saved by it's
internal number. What I am trying to do is, in a third sheet (File3), type in
an external number and have a lookup search that particular file name for a
certain cell reference, and return that in the sheet I am working in. I would
also have to do this without each individual part file open.

Example:
I am working in File3.
I want to lookup the weight of part number 12345.
File1 lists in cloumn A '12345' and in column B '88-459'
A file named '88-459' (along with about 100 or so other files) is saved in
'C:My Documents' on my computer.

What I would like to find is a way to lookup the weight in file '88-459'
when all I have is the number '12345' and a sheet that interchanges the two
numbers. Again, this has to work when neither sheet is open, as I would have
to open too many files at once.

I've tried INDEX, but that seems to only work when the file is open. I've
tried a VLOOKUP, but since each file name is different, I have to manually
change the formula for every different occurance. Any suggestions?