By installing a localhost onto your computer you are basically creating a mini server on your PC. You now have a test platform to check out WordPress plugins and page/post layouts before updating your site. Also I use my localhost as a working backup, I download my site to my localhost just in case my backup failed. There are basically 3 free localhost server software that I know of: MAMP , XAMP for MAC or XAMP or WAMP for Windows PC. I personally use WAMP but the choice is your. Below is 3 YouTube videos showing you how to install a localhost and then WordPress onto your computer, either a MAC or Windows.system. If you run into problems on a Windows PC please leave a comment and I will try to help. I had many small 'got ya' type problems that I could possibly help you with. Be careful when installing to a dual boot system, as you can install the program on the wrong partion, also when I uninstalled from my Win7 system it also removed the program from my Vista system on my dual boot. When editing wp-config.php I had to use a program called Notpad++as regular ' note pad' caused problems. Notepad++ is a free program. First is MAMP for MAC. This is the Windows version using XAMP This is an alternate Windows version using WAMP. This is the one I use and recommend.