Forget the CD that came with your new computer add-on.
When you buy a new printer, digital camera, webcam or other gadget the plugs into your computer, you're likely to get a CD with the software needed for that device.
That's all well and good, but it's often the best idea not to use that CD. The drivers and other software included on it are likely to be out of date. This isn't good as there are probably newer versions of the software available for free which will have had problems fixed since its initial release and sometimes have extra features added. You're always best off with the latest version.
Some manufacturers include a mechanism to auto-update the software to the latest versions, but the quickest way is to use the trusty Google. The best search you can use is something like:
epson 870 xp driver
or
creative optio vista driver
Look down the list of Google's results until you find one from the manufacturer. Sometimes you'll be taken to their main support and/or download page where you have to search again or browse for the software you need, but if you're lucky (and the manufacture's done a good job with designing their website) a direct link to the download page will come up top of Google's results.
Really, the only time it makes sense to use the CD is when nothing is available online (unusual) or you are somewhere without an internet connection (is there anywhere left?!)