With the installation of this patch, make sure that you're also updating your Windows XP drivers. Many of the settings for the game are actually setup with your Windows XP driver. This makes it necessary for you to do so to properly play the game. Although the game doesn't require the use of these drivers, they do make things easier. If you have a good working graphics card, an integrated sound card, and a fast Internet connection, then you should be fine with your game.
When downloading the patch, be sure to keep any programs such as antivirus, registry cleaners, or other tools that may have been affected by the patch out of your system. This will prevent any further damage done by the corrupting of the files. Once you've downloaded and installed the patch, you should not install any additional programs that are downloading the Black Ops weapons, gems, etc from any location on your hard drive. After you have finished with installing the patch, you should reboot your system to finish out the installation.