I would like to upgrade the CPU on an old HP Pavilion ze5730us. The motherboard is listed as model HP 0850, version N5570. However, I have been unable to find any specs for this mobo (from other threads, it appears not to be actually manufactured by HP). I would like to upgrade the CPU (currently Intel Celeron 2.8 GHz <Northwood, 400MHz? fsb <qdr>, 256KB L2 Cache, mPGA478B <FC-PGA2/FCmPGA4> platform, 478 pin). Any insight about whether a CPU upgrade is possible, and if so, what upgrade options are available would be appreciated.