First of all a main thing is, any Desktop PC can support wireless internet connection. Before connecting it, make sure that your desktop PC is free of unwanted spyware and other harmful files which could make a desktop computer wireless connection slow down. If you plan for already working PC then you should scan your computer for spyware and infections because they will steal your system resources.
Lets assume you have an internet connection and cursing the web with ease. You should have a cable modem connected to your desktop PC. Then, you need to purchase a wireless router. If you have never owned a wireless router before grabbing a expensive model probably will not benefit you all that much unless you plan receiving a wireless internet connection from inside of multiple story building. In this case a more expensive router will offer few features that are worth the money. Then the thing left is Wireless PC Adapter. There are two types of wireless networking components
Wireless USB adapter
Wireless PCI adapter
Both the devices will be provided with the setup CD-ROM which installs everything you needed to configure and use your PCs wireless internet connection.
Wireless USB adapter is the easiest way to connect and make your desktop PC wireless. In this the advantage is signal strength which is considerably weaker than a wireless PCI card. Most people experiencing no problems with the signal strength as long as they stay within range of the wireless router that is sending out the wireless signal. Then, installing a wireless USB adapter plugs into any available USB port. It will take some seconds to start work; you can straight away connect the USB cable to the port and start using wireless signal.
Wireless PCI card, it enables high performance wireless connectivity for your desktop PC with extended range. Simply remove the side panel from your PC and insert the wireless PCI card into any one of the white slots inside (more white PCI slots will be available). Then, install the card as per the directions given in the manual that will be given with wireless PCI adapter. This will be the best thing to install, because it will take some steps configure by following the instructions you can ensure a smooth installation and launch your wireless connection.