Sort of, the first one simply tells the system to request a repaint given those conditions. The UpdateWindow(hWnd); function on the other hand, allows you to request an update when you need one. If...

WindowClass.style = CS_HREDRAW | CS_VREDRAW
This causes the system to call request a repaint of the window when the width of the window is changed (CS_HREDRAW) or the height of the window is changed...

The default constructor is just used when no other constructors have been declared. To create a no-arg constructor (override the default constructor):
class MyClass {
public:
MyClass();
};
...

A few things: first of all, make the second if statement else-if; second, make the last else-if statement else. Also, pushups should be >50/>30. You should be more carefull with your brackets too:...

I believe what you are looking for is the EnumPrinters function in the Windows API. http://msdn.microsoft.com/en-ca/library/dd162692(VS.85).aspx

I'm not very experienced with threads in C++, but from what you said, it shouldn't make a difference in the amount of time it takes to empty the buffer. Have you tried it on another computer? And...

And did you download the SDK?