You need an OS disk to (re)install the OS or a recovery disk or boot from the recovery partition to go back to factory conditions.
A quick and dirty way is to just make 2 new users and delete all existing users, then delete all folders with company data that remain.
Kees
I have been given a computer that I am going to pass on to a friend in need but there is a lot of information on it as it has come from the company I work for. How do I format it back to the way it came as if new without losing the operating system. It is running xp professional. I formatted my laptop once but it was vista and does not work for this one which is desktop.

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