Have an Acer Aspire 1 notebook running Win7 starter, which only really gets used in the car. And not often. Used it the other day where it initially spent ages updating everything.
It's now stuck on what appears to be minimum screen 'brightness'. I'd set up my own power saving settings which worked ok - but even going back to the defaults makes no difference. The slider at the bottom of the power options page on the control panel is at minimum an can't be moved.