I bought a Dell laptop in September last year, loaded with Vista, but downgraded to XP. My gf is now looking to buy a new laptop and have been looking at Dell again. However, Dell now want £40 to downgrade Vista to XP. If we bought the new laptop with Vista, is it possible for me to downgrade to XP with the discs I was supplied with when I bought my laptop, thus saving the £40, and if so, how hard is it to do?!