Trouble Downloading Images with Cable

I purchased a generic USB download cable for my 5D and tried hooking the camera up to my computer, which is running Windows XP. The computer doesn't recognize the camera as a separate drive. I've tried downloading the driver from Minolta, even though it's not supposed to be necessary for computers running XP. No dice. I'm wondering if there's a special trick to this, or if the Minolta download cable is proprietary, or if there's something else I'm missing. I will eventually purchase a card reader, but for right now I'd like to get it working with the cable I bought. Any suggestions?

Thanks.

Usually the camera can work in two modes: printing mode or computer mode.
Maybe it's set in printing mode?
Usually you can change it from a camera menu, but I don't know Minolta well enough.

I checked the mode. The two possibilities are print and storage. It's set on storage mode, which is what the Minolta website recommends.