black screen with Ati X600

After installing Suse 9.3 at restart , the screen of my monitor is black color stopped , the same installing Suse 10.0. My computer has an Ati X600 PCI -X graphic card and think there are a disonance between the syncronisme of the monitor and the card.I have probed all graphic modes at the restart of Suse, but always the same thing happens. Anybody has the answering to the problem?.Thanks. jose FC