What are the differences between New Inspiron 15 (N5040) and Inspiron 15R 2nd gen?

I am looking for a laptop for my wife.  She will be using it for email, internet, facebook, photos, itunes, and simple Word docs.  She will rarely be moving it; mostly around the house.  The price difference between a N5040 and a 2nd gen 15R is enough to make a difference.  I think she'll be okay with a N5040.  But, I'm not sure what the differences are between the two 15 inch laptops.

Can someone tell me or explain to me the differences between the two?  Thanks.