I just got the ATI Radeon 2400 on Windows 7 and there are no colors showing ! only blue (I guess) and black.
What can be the problem ?
You may try completely uninstalling the ATI Drivers. If you go to your Start Menu, then right click "Computer", you can select "Manage". Once inside, find Device Manager and expand the category that says "Display Adapters". Right click it and hit uninstall. When the dialog box comes up asking if you're sure, select the option to delete the device drivers. Proceed with that.
From there you'll notice your screen resolution will go way down. If this fixes the color issues, then attempt to re-install your drivers. Use an old version if you have to. If this does not fix the color issue, it could very well be a hardware problem. Most likely the video card or the monitor. Test the monitor first by borrowing one from another computer. If that monitor still gives the color issues, you might try replacing your video card.
Make sure that your cables are plugged in all the way. When using VGA cables, if it is not plugged in all the way, it can cause discoloration like you're experiencing. If your plugs are in completely, you may want to try a different cord. If all of the pins are not connected, it will cause the issue.
Sometimes the VGA ports on the graphics card are a ribbon and then go down and plug into the graphics card. If you're using a port like that, you will want to make sure that the ribbon is also fully plugged into the graphics card.
Do you have another monitor that you can test it with? If your monitor has faulty wiring, it could also cause the issue.