hi new,
well, those parts may be "new" in a box, but, they are from 2006 or so. So: they manner in which the parts have been stored for the past five or six years may be an issue. Humidity can damage motherboards, and, capacitors can go bad over time, even if not being used.
That boards uses DDR2 memory: are you sure that the memory is functional?
Did the thermal interface material on the cooling fan/cpu fan harden? Did you use Arctic Silver 5 or some equivalent, freshly applied?
Was there an old CR2032 battery installed in the board? Is it still there? Did it leak?
Do the caps on the board look OK?
Name brand and model number of the DDR2 memory?
I am not sure what you paid for the gear, but, newer gear at the low end can be had very cheaply--can you return these archeological relics?