Hello, I need to format my hard drive but the problem is that when I boot my pc with Windows XP cd on it don't start the setup so I tried with an MS-DOS startup disk but it happens the same, it just go to Windows.

if your trying to boot from the cd when its in youl need to restart your pc, and whens its booting it should say press any key to boot from cd . . . .

if its more complex than that please post of your pc specs,
thanks