How do I clear everything from my computer?

I have so much junk on this computer,so how to in to delete everything( all browsing history, everything) and make my computer like new when i got it? Just needs a good clean up.How do I clear everything from my computer?
An easy way to make your computer as fast and clean as the day you got it is to simply reinstall the operating system. If you are using windows, which I assume you are, then just insert the windows disc, reboot, it will tell you to press a key to boot from cd/dvd, do so (if it never says this, make sure you are using the correct disc, and then try again. If not you may need to go into your BIOS, typically F1 or Delete, and change the boot order so that CD is first. When it asks you if you want to repair or format, choose format. It will format the HDD and install a clean copy of windows.





If you do this ALL data will be erased, so make sure to create backups of anything you need. Also you will more than likely need to reinstall graphics card drivers (if you have one) unless you install windows 7 which is really good with running hardware without drivers, as well as numerous updates.How do I clear everything from my computer?
If you have the recovery CD then it's easy,follow the instructions that come with the disk,first it will format you hard drive,that is erase it,then it will install the operating system and other software,putting the computer back to where it was when you pulled it out of the box. The first thing after you get this done is to update your system,for windows it's windows update,then to other places to get software you had before etc.
pop in the recovory cd with your computer.
Reinstall windows with your installation CD