If you see parts with exclamation or interrogation marks in the device manager as shown in see missing drivers
, you might need to find drivers if you want to take advantage of these parts if Windows is not able to install them automatically (see install a driver
A CD in the closet
First of all, most computing devices come with CDs containing their drivers in case you need to reinstall your computer. Take a look in case you kept these CDs. If so, just insert them and follow the installation instructions.
Otherwise, you must identify the brand and model of the part. For a printer for example, that information is always on the device itself, sometimes on a label on the bottom, sometimes prominently on the front. For an internal part, it is better to note the brand and model of your computer, unless it's a computer that you built by yourself. You can then do a search on Google to find the website of the manufacturer, like Dell for example. And then you can search for drivers for your computer inside the manufacturer website, there is always a section "support" or "download" where you can find drivers of all models.
You have no CD in the closet and no way to know the brand and model of your device, as long as you know what is the device, like a webcam or a sound card, you can download a massive driver package at driverpacks.net and burn them all to a CD. Then you can use the device manager to install the driver
automatically from the CD if there is one that matches the part you are trying to install. This trick is very effective and almost universal!