Modern computers interact with many kinds of external devices, which have lead to a state where device drivers (DD) account for a substantial part of the operating system (OS) code. Currently, most of the systems crashes can be attributed to DD because of flaws contained in their implementation. In this paper, we evaluate how well Windows protects itself from erroneous input coming from faulty drivers. Three Windows versions were considered in this study, Windows XP and 2003 Server, and the future Windows release Vista. Our results demonstrate that in general these OS are reasonably vulnerable, and that a few of the injected faults cause the system to hang or crash. Moreover, all of them handle bad inputs in a roughly equivalent manner, which is worrisome because it means that no major robustness enhancements are to be expected in the DD architecture of the next Windows Vista.