Download original file in Matrix theme

Hi all I have been racking my brain trying to find a solution to this.

I am trying to set up so a logged in client can download an original file. At the moment it opens the file very large in another browser window. I just want them to download it to a location on their computer. There must be a way to do this, I have tried different methods and ended up stuffing up my test site, so obviously I am too stoopid to work it out.

Unfortunately I am not as clever as you guys and don't the programming knowledge you have. So if anyone has a solution, please try and keep it in noob talk for me.

Cheers
Mick Brown

Gallery version = 2.2.4 core 1.2.0.6
PHP version = 5.2.4 apache
Webserver = Apache
Database = mysqlt 5.0.45-community, lock.system=flock
Toolkits = Dcraw, Exif, Getid3, LinkItemToolkit, Thumbnail, Gd, ImageMagick, NetPBM
Acceleration = none, none
Operating system = Linux fusion.websiteactive.com 2.6.9-55.ELsmp #1 SMP Wed May 2 14:04:42 EDT 2007 x86_64
Default theme = matrix
gettext = disabled
Locale = en_US
Browser = Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_5_2; en-us) AppleWebKit/525.18 (KHTML, like Gecko) Version/3.1.1 Safari/525.18
Rows in GalleryAccessMap table = 399
Rows in GalleryAccessSubscriberMap table = 629
Rows in GalleryUser table = 7
Rows in GalleryItem table = 617
Rows in GalleryAlbumItem table = 36
Rows in GalleryCacheMap table = 0