Find feature not working

I am using Excel Home and Student 2007 on a Windows 7 platform. I have a lengthy file which I must correspond to another (photo) file, and I need to determine that all names in the picture file are also on the excel file. I keep doing a "find" to locate the info I am looking for, but the system comes back telling me (98 times out of a hundred) that the information is not contained in the file. This happens, even if I do a test "find" with the actual data I am looking for already showing on the screen. Example, I am looking for a part number - 226688G -. I am in the Excel file, and can see that part number on the page. Yet If I go to the "find" feature, the program still tells me that the data cannot be found anywhere in the file. I have something like 3500 files for check and really need the "find" feature to work.

I thought maybe I needed to update my service pack, but when I tried, I was told that it was incompatible with my system. I checked my version number and it is 12.0.6612.1000.

Any help would be greatly appreciated.

Also - check for any spaces or invisible characters in your data (if you are trying to find exact matches).