"FIND" tool not working

[egptech]

I have a table in my DB with 1109 records. Each record has 27 fields available but not all fields are used for all records. Until recently I have been able to use the Find feature to locate specific pieces of information within the various records. (ie; I was able to enter a serial number of a single piece of equipment and have the FIND feature return that serial no.) Now it will not find the item, unless I specify the exact field the item is in. I can no longer search the entire table for a single item. I hope someone has seen this before.
Gene

 

[egptech]

Added Information;
The FIND function works with all my other tables; it does not work with the aforementioned table or a form based on that table.

I saved the table as an excel spreadsheet then imported that spreadsheet to a new table. I can now search the data in that table. I renamed the old table to tblIDTagsOld, named the new table tblIDTags and tried to search in the form based on tblIDTags. Again the FIND function failed, although it works to search the table. I createda new form based on the new table and FIND works on that form.

Obviously I have fixed the immediate problem, however it would be great to know why this occurred and how to prevent/correct it should it occur again.
Gene