I have an ATI Radeon 7200 and Trident onboard(can't disable this one) video cards. I tried to install Suse 9.2 several times, but the screen turns black when i'm trying to configure the graphics card. I also tried installing Suse 9.1, but it didn't work. Please help. THank you.

"Trident onboard(can't disable this one)"

Contact your motherboard or computer manufacturer. There is always a pin somewhere to turn off the onboard video card.

sadly this one doesn't.... there is no pin or no menu in cmos....
is this causing my problem?

"sadly this one doesn't."

You've contacted both Computer manufacturer and motherboard manufacturer, and been told, by both, there is positively, no pin, jumper or other setting to disable it?
If not, contact them.

Otherwise, yes, that is your problem. The system is probably not able to pick between the two safely...

A few comments: First, there should be some way of disabling the onboard video via BIOS, however, if not you could temporarily just go with the onboard rather than the Radeon. Secondly, if the screen is going black, it may be a framebuffer issue. Assuming you are using lilo, uncomment the "vga=normal" line in lilo.conf (don't forget to rerun it after you save your changes) and/or you can pass in vga=normal as a boot parameter. As general comment, if you are attempting to push a monitor beyond its capabilities it will go dark in order to avoid damage. The "fix" for this issue is of course to just use settings it can handle. Similarly, try using a lower resolution and lower color depth - as long as the monitor is reasonably modern, it should definitely be able to handle 1024x768 with 16 bit color.

Don't know if that will help but it's something to check. Good luck with it -- J.W.