Do the fans in the power supply run? Are there any "beeps" or series of "beeps" when the computer is trying to boot? According to this:
you must have at least BIOS P10 or greater (here's the latest BIOS; P19):
Also take note on the "Supported Processors" page:
" The following board revisions (AA numbers) support these processors:
C45439-301 or later
C45441-301 or later
C44953-300 or later.
See the board revision note, below, for an explanation."
Below:
" Board Revision note: A small bar-coded label, similar to the diagram shown below, can be found on the component side of the desktop board. The numbers following the letters "AA" can help identify the type and version of your desktop board. The AA contains a 6 digit main number, and a 3 digit dash number (the 3 numbers following the "-".
The statement "...or later" refers to the dash number of the AA (the three numbers following the "-"). If this number is greater than the number listed in the table, the board supports the associated processor(s).
If your 6 digit main number is not listed in the table, contact your system manufacturer for processor support information."
Make sure you have the proper cpu and BIOS installed.