Loading XP pro over XP home version

I have a Compaq computer with Windows XP Home. I bought Windows XP Pro OEM by mistake and it won’t load. Microsoft’s advice was to comtact Compaq. Compaq’s help was to F-disk the main drive and fresh load the XP Pro. There has got to be another way to install Pro without a complete drive wipe and reload. Isn’t it?

Every time I try to load XP I get the message that the system I’m trying to load is older than the current operating system and the install stops.

160 points