how can i upgrade my processor

Solution
Even if you do have to update the BIOS, what's the problem in that? It's a fairly simple process, and even if you don't need to do it, it's never a bad idea to update the BIOS before a hardware upgrade. Just make sure the PC has continuous power during the update, and don't touch anything while it is updating. You can upgrade the processor to a Core 2 Quad, like the Q6600. Update the BIOS to be on the safe side.
As long as it's a desktop PC you should be able to replace the processor. You'll have to find another processor that matches the lga 775 socket on a website such as newegg or amazon. Once you do that, You should be able to remove the heatsink from the mother board, take the old processor out, clean of the heatsink, put the new processor in, put some thermal paste on, slap that heat sink back on and call it good. There are plenty of youtube guides that should be able to help you out here as well.
 


bro i talked to few persons and they said that you need to do a bios upgrade.
 


There is a chance you might need to do this. Typically a new processor should be recognizable without the bios upgrade, but it may not run 100%. I'm unsure as to if this computer has any applicable bios upgrades.

 
Even if you do have to update the BIOS, what's the problem in that? It's a fairly simple process, and even if you don't need to do it, it's never a bad idea to update the BIOS before a hardware upgrade. Just make sure the PC has continuous power during the update, and don't touch anything while it is updating. You can upgrade the processor to a Core 2 Quad, like the Q6600. Update the BIOS to be on the safe side.
 
Solution
Your board is a 775 pin, so you have the option of swapping out that core2 duo for a Xeon quad core that will run faster, cooler and be a LOT cheaper to buy. Plus, as the come out of old servers, they wont have been over clocked and abused.

My daughters 775 PC went from an E4300 to a Xeon E5450 for £25; £13 for the cpu and £12 for a new cooler; however, for your chipset, you would need an E3 series Xeon. it was a night and day improvement, even boot up times were more than halved.

You can read about it here https://www.delidded.com/lga-771-to-775-adapter/2/