Nvidia geforce display locked above resolution, can't start windows?

Hi, I got myself a used Dell Vostro desktop pc (winXp) with an nvidia geforce 8300 graphics card; staring at the screen, when reading news or long documents made the eyes hurt a little, so I checked all the screen resolutions and monitor settings; then I realized the nvidia drivers were outdated (2007) so I updated them, but when I checked the new menu, changed the resolution to see the top resolution, but suddendly the monitor went black and reads “unable to display resolution” and since then I cant start windows, even in safe mode. I hope there is a workaround, or a manual reset to the display, so I can do something because the good ‘ol useful desktop pc turned into a big empty useless box with lights…