Insert Windows CD, go to BIOS (usually F8 or F10 or F12 on the black screen startup) and select boot from CD. Windows will wipe the HD clean of everything so you lose your music, docs, p0rn, programs, everything and start fresh. You will obviously need to back up everything you value.

Also, because Windows XP is antiquated and sucks (Win7 automatically does this all for you), you will have to download video drivers and motherboard drivers so your display will work properly and all your motherboard's functions (sound, ethernet etc) will work properly.

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1985 CA 300D Turbo , 213K mi