You really don't want to have to exchange your motherboard, though. So, you've already purchased your BozoGrafix video card, and your monitor will now only display 16 colors. Make sure you properly uninstalled the hardware you're replacing. The same procedure will work for most hardware. The procedure for installing a new hard drive would be a little different and more complicated.
Most people install the new drive first, copy the old one to it, and then remove the old one.
However, any main component that has an entry in the Device Manager should be properly uninstalled from the Device Manager list before physically replacing it. If you're not sure, don't delete it but rather rename it to something like slugv.bak. Renaming the file will disable it, but if you end up needing it for some reason, you can restore it by changing the name back to what it was. Make sure the hardware is properly installed physically . This may seem unnecessary, but it's is often the cause of a problem.