Could you expand on the display problems?, why do you feel you need to re-install? if it is a matter of missing/corrupted system files you can run sfc to put them back. If a re-install is really needed then just put the cd in and run setup, this will "over write" windows and replace any files etc that are needed whilst at the same time keeping all you settings and work etc.
Post back with the exact nature of the problem and we will help you out.
Have tried correcting this via the monitor buttons? sounds like this what the prob is, on the front of the monitor there are usaully buttons that enable you to "shift" the display, if everything else is ok I.E display ok then this is more than likely the problem