Hi Imogenn and welcome.

You don't give us much information.

What do you mean by the internet won't even open?  What error messages do you get?  Has the internet never worked?  What software have you installed?  You don't tell us what you have tried. 

If it was working when you first used it, perhaps you should return the software to factory settings as the problem is probably something you have installed.

If the Vaio was faulty from the start, you should take it back to the shop where you bought it and ask for them to fix it for you or change it for another one.