If you boot up your computer with the 9200, does the bios of the card and of the motherboard show on the screen? If you are not sure since the display takes to long to wake up, does the display wake up out of sleep mode and is blank then, or maybe you manage to get into bios by hitting the korresponding key?
When this is the case you can probably boot winxp into command line or eaven save mode, then you have a driver mess up somehow.
If this doesnt work you might have some bios setting that prevents the 9200 card from working.
I guess the cards are both AGP cards?
I think there are diffrent AGP standarts, 4x,8x and a low voltage 8x. While A motherboard supporting the latest one works with earlier cards together it doesnt always work the other way.
Did you use the same cable?
It might be the monitor doesnt automatically switch connection and if you have changed to the diffrent plug on the monitor its black till you switch input.
hope this helps