bootup will be a lot faster, loading of applications and the likes. but as for processing then you're out of luck. not much you can do with portables, just add ram and change hard drive.
Sorry, not much you can really do. The only real way of increasing performance is to change the CPU, but it is soldered into the motherboard so it cannot be done.
The best thing to do is to reinstall Windows (after you backup important data). Over time Windows Registry can become bloated with entries that are not necessary which can slow down the netbook by a little bit.