Windows vista was proven to be screwier then its older version XP, which i have, and windows 7 is a mix of both so....
vista had the protection rules a bit too extreme (asking for confirmation too much), user of windows have been for a too long time assuming that being administrator always with full access with no protection was a good idea (and they still think so) but it's the worse idea ever to run windows as administrator at all times (just like it goes for linux and macosx, both even ask you to type your user password not only to click a button). vista put a fix at this but they went on the other side (too many confirmation for privilege escalation by default), which people who didn't use their computer correctly hated. at the same time oem installed it in computers which shouldn't have had vista. Windows 7 is still vista only with a less strict security configuration and it's not being installed in computers not able to handle it. (it's also able to scale a bit better on low memory environments but that won't change anything for who has 4gb of ram). Afaik windows 7 is a vista revision (vista = 6 win7 = 6.1).
bsod and similar faults of vista, which are no more in win7, were only oem fault caused by lack of proper drivers day 0, if you tried to installed the same things you would install in vista when it came out you would have the same precise issues on win7.
Also the whole issue with the applications which modded the kernel in order to provide security is another thing which they did well but was refused.
Essentially they did what usually shouldn't be done in informatics when you've end users: revolutionize the software fast to fix long lasting issues.