The first thing to check is that she has disabled any firewall, or configured it to allow you to connect.
Next, make sure that she has shared a folder (or folders) - right-click the folder and choose sharing.
If that does not fix it, check out the useful advice at click here
If you are still stuck,post back, and include which version of Windows you are both using, and how you are connected (e.g. via a crossover cable, router etc).