Kindly help, i need to upgrade my PC that has 2.6 GHz Dure core, 512 MB and 60 GB HDD what is the best recommendation?

We'd be happy to help, but we need a lot more information.
If it's a prebuilt machine, what make and model?
Notebook or desktop?
What model motherboard?
What model CPU?
What model graphics card, or is it using onboard graphics?
How old is it
What do you want to do with it?

Would you consider replacing it?