My MoBo light its green, but the pc won't boot up

[Dingotm]

Well has the tittle says, i recently bought a motherboard with a new cpu wich are a p6p67-m and a intel i5-3550, i instaled everything, the motherboard seems to have the light on but when i tried to boot up, the psu was working in my old pc having no problems, same for the video card, if there is someone that could help me i would be very appreciated.

ps: some extra information

Psu: 460w cool master
grapic card: ati hd 5670
Ram: 4 gb ddr3 1600

 

[satyamdubey]

that is coz you have installed a third generation core i5 processor on a second generation core series mother board. You have to update your motherboard BIOS before you can use your computer.
To upgrade your BIOS you need to first install a sandy bridge cpu on the motherboard...flash the motherboard with relevant update and then install you core i5 processor. Sadly this is the only way to get it working

 

[Dingotm]

Update: I can't afford to buy another cpu, so i tried to fine if there were another malfunction, there were something about the ram that it says the motherboard can't hold up to rams with 1600Mhz so i have to change the configuration of the bios. I don't know if this is the problem, or i just need to update the motherboard. thanks btw to satya for the answer.

Ps: Now the pc boot up, but it won't show on screen.