Changing a processor?
No you can't but that has absolutely nothing to do with them being laptops. Both of those laptops are socketed and can have their processors changed. The Asus is a socket M with a dual core and the Dell is a socket 478 mobile pentium 4.
Changing a processor?
Since they are laptops...you wouldn't be able to do that. If you want a faster processor you would be better off just buying a newer..better laptop! Sorry