What's the native resolution, 1280x1024?
(I can't find info on a 1917A)
Try another user account.
If you need to, set up another user account with admin privledges.
See if the problem persists.
if not, it is a software problem in your account.
Might also download the ATI Display Panel, and see if resolution adjustment can be made there:
http://support.amd.com/us/gpudownload/Pages/atidisplays4-5-7.aspx