You have a laptop, so god fucking knows what's happening there when it comes to drivers.
Also, I don't have experience in Windows 8 (I bought it, but I can;'t be bothered to reformat my machine). However, some video drivers have a option that makes you decide who is going to do the stretching of a resolution: The GPU or the Monitor and if it'll keep the aspect ratio or not.
To make things simpler, let's say you have a game that outputs in 640x480. Your monitor is 1920x1080. There's a Scaling option on some drivers (I don't know what it's called on AMD GPUs, but it was scaling on Nvidia ones) that allows you to set who is going to scale that content up and how.
In your case, as you're using a laptop, i'd say leave the scaling to the GPU and, if possible, keep the aspect ratio.
Now, that windows setting thing you talked about - I don't know if that's a Windows 8 thing or what, but try to find an overall option on the GPU level.