Soundmax is software which comes bundled with your soundcard drivers. It's that part of the package which helps you configure audio devices available in your system. Getting the software back is easy because all you have to do is to re-install the package from the support CD. But before you do that you should go to Control Panel > Add & Remove Programs and find the entry
Soundmax... and click Remove. Perform a restart of your computer and then install the sound drivers package again using the autorun menu from your support CD. Soundmax belongs to sound cards that are incorporated into the main board.