I recently bought a new ATi radeon 3650 HD AGP 512 MB video card. I currently have a nvidia fx 5200 128 MB video card in my Dell Dimension 4600. Will I encounter any problems down the road as I replace the old card for the new.
You shouldn't have any problem. You'll need to hook the 3650 to your power supply using a 4-pin molex. If you don't have a an open power 4-pin power connection, you can get a 1-to-2 splitter for very little $. This should be the only difference other than swapping one card out for the other. Further, use the following doc as reference: