see if you can find ATI display adjustment settings in the ATI control panel.
Also what happens if you lower the resolution to 800x600? or 640x480? does your monitor support 1024x768?
When you installed the drivers did you make sure to uninstall the old ones? You could try this it`ll uninstall your drivers completely and then try reinstalled the new ones:
Also to use the ATI catalyst control center you need .net framework here's a link for information and where to get it: