Hi elainetj,
Most things are possible but, generally speaking, laptop computers are not designed to be upgraded. The components in the system are balanced to a performance specification and if you decide to upgrade the processor, you will probably need to look at the graphics ..... the screen ...... the chipset ........ and so on. It is not possible to upgrade some of these.
The VPCEB3J1E is designed as an efficient everyday laptop at a reasonable cost. Adding an i5 processor for £150/£200 plus fitting or an i7 for £250/£280 plus fitting is an expensive option when you will still have Intel HD Graphics and a 1366 X 768 resolution screen.
I would max out the memory to 8GB and see if the Vaio works for you and is fast enough for your normal use without paying out too much. Then decide what to do.
