I was also wondering whether I have to update my BIOS so that it can support other CPUs. I tried putting in an AMD Phenom II X4 3.2GHz Processor (955 Black Editions), but it could not supported it. So, may anyone please answer my questions?
You've already answered your own question. Your hp system has a 250 watt power supply; you can try replacing it with a higher rated one. A 500-600 watt antec, corsair, seasonic, or enermax is what I recommend based on twenty years experience building systems. It will leave room for a video card upgrade later. Don't think a cheaper brand will work just as well; many fail under load. Mine went up in smoke after 3 days. My best guess is that the board has a limit of 95 watts for the cpu, which excludes alot of phenom II's which are 125 watts. My newer board has the 8 pin 12v port for high end phenoms. The bios update won't change any limits on what your board can run; it may allow it to recognize certain cpus, but the phasing design is what makes it stable with higher wattage cpus. If you decide to change boards, be sure you can get another windows coa sticker; your windows installation won't load with a non hp board. Next time you buy an oem system get the cpu you want up front; they really aren't designed for upgrading the cpu.