1. a )Turn of your PC completely, unplug your PC, and wait a few seconds just to make sure all the capacitors are empty.
b) Touch any metal which is connected to the ground with your barehands before touching your graphic cards to remove the static electrical charges from your body. A strong static electrical charges could damage any electrical components. This is just to be 100% sure, but If there isn't any metal connected to ground near you, just skip 1 b) with the hope everything will be just OK. Skipping 1b) could damage your card, it only could be/perhaps/probably/ or it only happens sometimes, it doesn't always happens.
2. Plug your new HD4650 in the AGP slot, there is only 1 slot that will perfectly fit the graphic cards. No problem here, as for the color of the slot , I have forgotten, my last AGP slot was 4-6 years ago.
3. Remove the cable to your monitor from the onboard graphic card and plug it in the new card.
4. Power up your PC, this time don't deactivate your onboard graphic from BIOS yet, just in case somethin' went wrong.
5. If nothin' went wrong your computer will boot like normal, after finished booting install the driver, either from the included driver CD/DVD or download it from ATI's website.
6. You will need to restart your computer after the driver installation.
7. After installing the driver and restarting the computer, test your graphic card by playing any games that you have. If everything is OK, you can restart and go to BIOS to deactivate your onboard graphic, and after that you can also deinstall it's driver from your windows. I said "You can", this means, you don't have to, but it is recommended to be done.
8. Enjoy your new HD4650
BTW : the card's type is just HD4650. AGP is the slot type name "Be sure not to buy the PCI-e version, you don't have this slot!"