I have an old Powermac 7200 and with my new router, would make a great computer just to browse when someone else is on the iMac. However, awhile ago due to problems with the monitor, I had to put a 13 inch Apple monitor that offered only 640x480. I have managed to fix the previous 15 inch one, but when I connect it, the only option is still 640x480 while I know it was giving me 1024x768 before. Is there a way how I can get it to those higher resolutions? I am running Mac OS 8.6.