1) Decide what you would like to do. Are you going to reinstall your operating system because of problems, upgrading your current version, or are you installing an operating system on a new computer? Make sure that you have the new operating system install program. Windows and Mac require that you purchase a CD or DVD Rom(s). Ubuntu and other Linux are free and can be installed from a flash drive too.
2)Back up your data. If you are reinstalling your operating system, it is likely that you will need to wipe the disk. Back up your data before doing so, as everything on the disk will be destroyed. If you are simply upgrading, it is okay to skip this step, but it is advisable to save at least the most important files on your computer.
3)Completely wipe all information from the hard disc. This will ensure that you do not carry problems over into the new install. For instructions on how to do this watch the video at http://www.youtube.com/watch?v=OfICZMMr0JM New installations of Windows and Linux offer to replace all data on your entire hard disk. So completely wiping it prior to installation is unnecessary.
4)Boot up. Turn on your computer and quickly enter the boot menu. The owner's manual for your computer or motherboard should have instructions on how to do this. It will show on the screen for a brief moment too. Select the drive that contains the setup disk (and be sure you have inserted it). Save the setting and exit.
5)Start the installation. It may take the install program a few minutes to load, this is normal. Once it has loaded, follow the onscreen instructions. If you are installing a new operating system on a new computer or reinstalling due to a problem, wipe the disk. Be sure you have saved everything that you would like to save before starting this process.
6)Sit back and relax. The installer may ask you for some information while it's installing, but for the most part, just waiting is okay. Near the end of the installation, the installer will ask you for last-minute information, like your name, the name of the computer, sign in name, password, time zone, etc. Do not be alarmed by this, none of this information can be used to identify you, it's all for personal preference.
7)Enter the product ID. If you are installing a consumer operating system like Windows, it will probably require you to enter a product ID. Look at the back of the CD case for the product ID or, indeed, on the case of the computer if the computer came with an OEM version of Windows. If you are installing Linux, this will not apply to you if it is an open source variant of Linux (for example: BackTrack, Ubuntu, Fedora), but will if it is a closed source variant of Linux (for example: Red Hat, HPUX, SuSE etc).
8)Reboot. Once you reboot, the computer will finalize everything and log you in. At this point, you may need to install drivers. Insert any disks that came with your computer or it's parts that are NOT an operating system, and allow the drivers to be installed (if necessary).
9)Allow updates. This is especially important in Windows. Allow the computer to seek updates and install them. Look for a "top 10 things to do" list for that operating system.
10)Install antivirus software. If you are using Windows without antivirus software while on the web, you are extremely vulnerable to all kinds of malicious programs. Before you do anything, even installing Firefox, install antivirus.
11)Use it! You're done, now what you do is totally up to you. Set a password, install programs, customize, create user accounts, etc. If you have any files you backed up, you may restore them now. Or, just enjoy the clean slate and redo everything, whatever you like.
