I want to upgrade my pc's processor from AMD Athlon IIx2 to AMD Phenom IIx4
as far as I know when you install an operating system, the hardware specs of the PC is being save in the registry
can I change my processor without formating my PC again (will it malfunction because the processor specs on the registry doesn't match with the system's registry?)

What motherboard do you have?

EMX-MCP61D3-iCAFE im just 90 % sure about the model because im not in my home now so I cant check it,, but as I remember that is the name of my motherboard the brand is EMAXX

If the information you gave about your motherboard is correct, that CPU is compatible with that motherboard.

Make suitable back-ups, respect the principles of ESD, and your operating system should accept the CPU upgrade under normal circumstances.

so it means that I don't need to reconfigure any file in my system's folder that holds the hardware's information?

Me too i think that's what he means, if i'm not misunderstanding of course.

I just upgared my pc with Dual Processor Motherboard cheers!

so it means that I don't need to reconfigure any file in my system's folder that holds the hardware's information?

You should be fine, go for it. :)

you can make up to 3 changes before windows asks you to go through the online validation process. even then, it is just an automatic connection and approval

If your mother-board support the AMD Phenom IIx4 processor only then you can upgrade the processor. Actually os reinstall is required when every time you upgrade or install a new hardware into your computer. But some time the system configured without any problem. But you need a back up for your important data. Then you can try this process.