How do I uninstall a OS?

If your planning on installing an alternative Operating System, then usually it's just a case of putting the OS disk into the disk drive and going through the prompts. There's usually a section for you to format the hard drive before installing the operating system. Formatting will delete the current OS, readying it for the new OS. Make sure you have backed up any files on the old OS that you may want to keep, preferably to another hard drive or to a cd/dvd.

You can't simply just uninstall an Operating System...because you are then left with nothing. Instead you install another operating system in it's place. For example if you want to get rid of Vista you would either need a disk and license key to XP or Win7. Depending on which you prefer to use the installation is slightly different but generally speaking you would use the disk and follow the on screen instructions.

Hope that helps.

I think you need to use the disk for another OS. Boot into the install disk and use it to format the hard drive. Then it will be without an OS.

I assume you want to install another OS the computer. So all you would need to do is put the CD/DVD in your CD/DVD drive then turn of the computer. When you turn on the computer (at least when installing xp others should be simmilar) it says "press any key to boot from CD". If you do that then it will boot from the CD and you can follow the instructions to format your drive and install the OS.

You can't uninstall a operating system, but you can just format the hard drive with a live CD. Linux or some other utility software that will run off CD or USB pen. Majorgeeks website; you can find software in there. Assuming formatting is what your on about.

either install another OS or remove the hard drive and manual format it with a magnet or format it with a Linux live CD

If you want to remove Windows Vista then make sure you format your hard drive because that is the easiest way