what you can do is find a windows 7 pro upgrade disk,
and a windows XP pro dell iso.
first to clean the HDD install ubuntu/linux and use the entire HDD
then install xp, download and install all drivers.
after that use the windows 7 pro upgrade iso to install windows 7 pro, and use the key provided on the system.
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since the bios can sometimes nag about the iso, and the current system, this is the best way to install it,
this was in my case on my mini 910