Ellen,
There is no such setting that we are aware of that would allow you to cut off a download. Usually a download may be cut off because of line noise or errors that are occurring while the file is being downloaded, the download is being sent to slow therefore the side providing the file stops the download, and/or any other number of possibilities.
You may want to make sure that the computer has no errors or conflicts in device manager, as it could be possible that if the modem or network card that she is using to connect to the Internet has no conflicts or errors on it. This can be checked through device manager, additional information about device manager can be found on the below link.
http://www.computerhope.com/win95er.htmAdditionally you should also have her make sure there are no updates available for Windows and/or any devices installed in the computer by visiting Microsoft Windows Update’s page at:
http://windowsupdate.microsoft.com Finally, if she continues to have the issue, you may want to consider trying a “download manger” these programs will help manage a download and if a download cancels be able to resume from the spot it stopped at. There are numerous types of these programs available, below is a link for a search done in Google for “download manager”.
http://www.google.com/search?sourceid=navclient&ie=UTF-8&oe=UTF-8&q=download+manager