Vicki, I format my computer about once every three to six months. It cleans it up and makes it run faster. To do this you need the windows disc it will guide you through the process. This wipes everything from the computer so you need to back up everything, including drivers. The computer I have is a HP and it came preloaded with a bunch of stuff I don't want.

Hi Vicki! I know your question was directed at Alice, but I wanted to add my 2 cents worth. As for the 'How?' its best to take your computer into a shop that does things like that. A good place to start is wherever you purchased your machine. My husband re-formats our computers at least once a year. Sometimes, computers have to be re-formatted to clear out a virus or malware that's made onto the computer. As for the 'Why?' Alice is right... over time your computer gets bogged down with stuff it doesn't need and which causes a lot of problems eventually. You should absolutely back up your files. If you take your computer to someone to re-format, make sure you can trust them to do what's necessary... including, backing up your design files.