Here my laptops resume from hibernation or sleep when I press the power button.
If I were to guess you want a pure sleep but that requires not only all the drivers but that all those support sleep.
I can't guess your Windows 7 install plan. It's much too hard on folk today. I strongly suggest you use the OS the S400 came with.
I installed all the drivers on my Lenovo IdeaPad S400 laptop so now i see the sleep option in the start button. but when i press the button again, the laptop still resumes from hybernation.