Have 2 Acer 5520 laptops bought within 2 weeks of each other. Vista Home Premium. Dual core CPU. What I was wondering, both are connected to same home wireless network. Snooping around computer I see that Gb used is within 3Gb of each other on "C" disc 2 machines but my 'top on "D" disc has 64.3 free and hers has 69.3 free out of the 69.5 they both started out with when new. Why the dif since they have been updated when required