Website Search Facility

We have a website which stores a series of PDF files, all of which are named using a specific convention; we are looking to add a search function to the front of this to see if it is possible to locate the file out of all of the files located in a specific folder.

I.e. search for part of the name of the file.

This website is hosted on a ASP server, there would be the need to be able to use wild cards in this as well. The files are not stored in a database and have simply been added into a folder online.

Ideally we would like some code which would provide a simple front end search facility for any users.