DSLR Noobe with a 7D, a bit worried !!!

After a lot of research I bought the 7D with 15-85 IS USM Kit lens. This is my first DSLR and I know its going to be a steep learning curve for me especially learning manual controls and then the functioning of 7D. But As I am clicking shots trying out different settings I found a few problems. Some of the photographs with flash look quite good when viewed zoomed out but at 100% the face of the person is blurry. Secondly photos without flash don't look as crisp as the ones with it. After searching some more on the net I found many people reported AF issues with 7D. Now I am really worried as since I am a complete noobe I won't be able to test fully and find out if there is really a hardware problem or I am doing something wrong in the settings. Please Help !!!