You need an upgrade version to upgrade without loss of programs.
If you but an OEM copy you can install without formatting but will need to load drivers and programs again.
An upgrade copy will run about 185.00 plus shipping on the Web. It will install over home without changing anything.
TIP: Be sure you are virus/spyware free before you start.
I just bought a new HP PC with their OEM XP Home. I would like to have XP Pro on this machine as it's been on my old Compaq for a couple of years with no glitches. What will happen if I install a full version XP Pro over the OEM? Will I lose files, programs, etc.? Thanks in advance.

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