Most desktop computers come equipped with the ability to connect to the Internet wirelessly. If you have an older computer, however, you may have to connect to the Internet the old-fashioned way -- with a cable. However, you do not need to toss out your entire machine to enjoy the convenience of wireless Internet.
Modem and Internet Service Provider
Since you will not likely be toting your desktop computer to a wireless hot spot at the local coffee shop, you must have a subscription to the Internet in your home or office. There are a number of Internet Service Providers (ISPs) that provide service over cables or over the air. Once you have subscribed, your ISP will provide you a modem and help you set it up. The ISP will also provide you with a username and password so that only you can access your account.
A router is the device that connects your computer to the modem, which then connects you to the Internet. Wireless routers send signals within a small area so that Wi-Fi-enabled computers can pick them up and connect to the Internet. Some modems have wireless routers built into them, so check with your ISP to determine if you need an additional router.
To ensure the best performance and protect your computer, install all critical updates. If you have a PC with Windows, download all service packs and other updates from Windows Update. If you have a Mac, make sure it is running with the most current Mac OS available. Perform these updates with an Ethernet cable connected to your router or directly to your modem before you purchase a wireless adapter, as different adapters may be compatible with different operating systems.
The key component to bringing wireless Internet to your desktop computer is a wireless adapter. There are two types. The first is a USB adapter, which plugs into one of your computer's USB ports. The second is a PCI card, which you install in a slot inside your computer. The PCI card is generally more powerful and can pick up weaker wireless signals, but the USB adapter is more convenient to use. Both of these types of adapters are widely available at electronics retailers and are formatted for PCs or Macs. Follow the instructions that come with the adapter when you install it.