can i change my processor on laptop dell inspiron n5030 6 gb ram intel core duo cpu p8700 2.53ghz 2,54 ghz

Solution
Maybe possible, but I would say not worth it. Even the best CPU you can get for that system (on paper) is pretty slow compared to anything made in last 8 years, and even if the CPU fits in the same socket it may not work. I'd spend $150 and just replace it with a older i3 or i5 laptop. You can find things like T410, T420 systems for well under $200.

You can also just try a clean Windows setup on a new hard drive, solid state would be best, but then you are spending about $40-50 on a system that is just slower overall vs a newer full faster system.
Maybe possible, but I would say not worth it. Even the best CPU you can get for that system (on paper) is pretty slow compared to anything made in last 8 years, and even if the CPU fits in the same socket it may not work. I'd spend $150 and just replace it with a older i3 or i5 laptop. You can find things like T410, T420 systems for well under $200.

You can also just try a clean Windows setup on a new hard drive, solid state would be best, but then you are spending about $40-50 on a system that is just slower overall vs a newer full faster system.
 
Solution
It depends on whether your P8700 is the BGA version or the PGA version. The former can't be upgraded, but PGA version? Maybe. It's also up to the firmware on your laptop.

Depending on what you do, you might benefit more from an SSD, which is almost certainly an easier upgrade (physically, may be a hassle if you have programs/licenses that you can't migrate easily).