It is good to see you have an understanding at least, crahak Just to expand on the driver signing issue: - it is only enforced for 64-bit Windows - it is a protection system to prevent unauthorised kernel mode code which includes modifications to existing drivers - audio drivers use UMDF now, so are not kernel-mode - the signing is done with the vendor's own PIC, not a "Microsoft stamp" - it is disabled if a debugger attached, so developing drivers is not a problem - in corporate environments you can disable driver signing, or create a CA to sign the drivers yourself for distribution - it is not only for stability through "certified" drivers, but for security to help protect against rootkit-type attacks Also, Windows Vista was the product of a massive amount of user feedback during beta testing, its design radically altered in response to comments and demands, so while it's not possible to create something that at least a few people won't complain about, a "best effort" can be made while still making advances in security, stability and features.