Difference between reinstalling the operating system and formatting the hard drive?

[herryjame]

Hello Friends.
Can anyone tell me that What is the difference between reinstalling the operating system and formatting the hard drive? I have Windows Vista and I want to completely delete everything of the computer and restore it to the original settings. Does reinstalling the operating system and formatting the hard drive both delete your data files and restore the system as it was when the computer was purchased? Also, the manual says I can reinstall the operating system by pressing the F8 key repeatedly when computer is starting.
Thanks.

[overtux]

If you want to restore it to the orignal setting you will formatting and reinstal completely the operating system.
When you format the HD, you delette all files so he become new!


But when you just reinstall operating system without formating, your files are saved!

ps: sorry 'i'm french