No, you have to release the Control key, then depress it again and select the file you want to add to your list.
Is this the the official 7100 version directly from Microsoft?
Was it a "clean" install or an upgrade?
Do you have any problem when you hit the Shift key and select the top entry and the bottom entry? Are they all highlighted?
Do you recall installing any new software that may have caused the problem?
To select items with the Shift key, you keep it pressed down and do not let go untill you choose your final file.