Assuming the Win2000 machine is in fact capable of running Windows 7, there's really no upgrade path, you'd have to install Win7 from scratch.
You could of course attempt to install Windows 7 onto the same partition as Win2000, that would preserve the Data files, but its unlikely any programs would run.
Additionally to that Win7 requires unallocated and un-formatted space to create an additional 200MB system partition. Which it can't do if all the Hard drive is partitioned prior to installing Win7.
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Phil AKA Vacunita
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Ignorance is not necessarily Bliss, case in point:
Unknown has caused an Unknown Error on Unknown and must be shutdown to prevent damage to Unknown.