Multiple Checkboxes in Search by Form

I have 8 products chosen by checkbox in a search form, they check the box to
retreive all the items entered for a specific product or products, they
should be able to choose more than one product, i.e. I want product 1 and
product 4, but need to be able to choose up to all 8. There are multiple
search criteria on the form. I have all the other searches working, but the
checkboxes. These boxes are checked when the data is entered into the table
via a new product change form. I'm using checkboxes because of the large
number of cretiera that could be possible and even our own people can spell a
product name differently making it impossible to search and get all the
information on specific product(s).