Which driver DO you have,
I have the WIA driver 453 and the Twain driver 453
I can't recall which it is, but you have to jump through hoops,. install the right one of the above and then THEN you may only be able to communicate with the camera via one of the bundeled programs, and there's three to chose from I and I can't recall which one of the there it is.
Eos Viewer,
FileViewer, or Zoomborswer... 
OR it may simply show up under "My Computer" in which case you right click, select properties and go from there..
It was all pretty archaic..
Anyway let me know what driver you do have and if you don;t have one of the above.