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By Windows 2000 Professional chipset for the Intel® Desktop Board D945GNT you mean a different chipset than Intel® 945G Chipset (the one installed on the board) so it can support Windows 2000?
If that is the case, a chipset cannot be replaced by a different one as all the hardware is meant to be compatible, most likely the board will get defective.
On the other hand, the motherboard in question is compatible with Windows 2000, you can confirm the information here, under "Discontinued boards".
Hope I hear from you soon.