bk- writes with news that documents from the "Vista Capable" class-action lawsuit against Microsoft indicate the software giant could be on the hook for as much as $8.52 billion in upgrade costs. "[University of Washington economist Keith] Leffler came up with his total upgrade costs by calculating how much it would cost to upgrade each of the 19.4 million PCs with 1 GB of memory and graphics cards or onboard chipsets able to run Aero, according to Keizer. Leffler put the maximum cost of upgrading the desktops at $155, while positing that the notebooks' integrated graphics would be more tricky to replace and would cost between $245 and $590 per unit. The total price tag for Microsoft would thus range from $3.92 billion to $8.52 billion and in some cases would include complete replacements of notebooks that could not be feasibly upgraded, Leffler testified. Microsoft in its response argued that giving litigants 'a free upgrade to Premium-ready PCs would provide a windfall to millions.'"