Hi A. Garcia,
Boot your PC into 'safe mode' then chnage the screen resolution back to it's original setting.
To boot into safe mode, switch your PC on and, as it is booting, keep tapping the F8 key. You should see a menu appear. Select Safe Mode from that menu. One in safe mode right click on the desktop, select Personalize and then choose Display setting. Use the slider to reduce the resolution of your screen and then click OK. You will be asked if this is the resolution you want so click OK again and then restart your PC normally.
This forum post is my own opinion and does not necessarily reflect the opinion or view of Microsoft, it's employees, or other MVPs.
John Barnett MVP: Windows XP Associate Expert: Windows Desktop Experience: www.winuser.co.uk | vistasupport.mvps.org |xphelpandsupport.mvps.org |www.silversurfer-guide.com