Please help. Criteria is not working for drop down box.

Hello,

I have a drop down box that I created the following 5 columns:
Product Name, Type of Product, Manufacturer, ID/Serial Number, and
Box Number. I originally had a button created, so that my end user
could query the "Manufacturer" column by typing in all or part of a
word. Once they typed in a work like "Windows" everything that has
the word "Windows" in the "Manufacturer" column would come up in the
table for them to print. Now, I've created a drop down box with the
columns Product Name, Type of Product, Manufacturer, ID/Serial
Number, and Box Number. The end user wants to be able to choose one
of the 5 columns, for instance Type of Product, and a window would
pop-up. Next they would type in Software, and everything in that
column with the word Software would come up. My problem is that I've
added the code Like "*" & [Enter Keyword] & "*" to all of the columns
in my query, but it will not work. It will only work in one column
at a time. Is there a way to change the code/criteria so that it
will go directly to the column they want to query? I would
appreciate any help offerred. Thank you.