DirectInput8Create() not working

Well for a start, you really shouldn't be redefining a DirectInput function, which is what you appear to be doing. Are you sure you have the right libs in place?

Second, it also looks like you didn't define DIRECTINPUT_VERSION, which the directX libs require you to define yourself - this tells it what version of DirectInput to include/utilize. For example, for the latest version of directX, just include the following:

#define DIRECTINPUT_VERSION 0x0800

and you'll need to place this definition *before* including the directinput header. Otherwise, it won't know what version to look for.

But, an undefined variable like that, would definitely cause your problem.
...edit, also make sure you're including the dxguid.lib library - that contains the definition for your IID_IDirectInput8.

alright, thanks a bunch:-)
That got rid of a lot of warnings that my compiler was giving me. the only things that's giving me a problem now is that it says: error C2059: syntax error : 'constant', even though there are no constants in my header file. what could be the problem here?

Well, as I said before, why are you redefining the DirectInputCreate function?
You'd want one of the following:

// This is a function prototype, but DirectInput8Create is already defined in // DInput.h/lib.
HRESULT WINAPI DirectInput8Create(HINSTANCE g_hInstance, (DIRECTINPUT_VERSION's type) DIRECTINPUT_VERSION, (IID_IDirectInput8's type) IID_IDirectInput8, LPDIRECTINPUT8* pDirectInput);

Or, this:

// This is a function call. Never place an object's data type beside it in here.
DirectInput8Create(g_hInstance, DIRECTINPUT_VERSION, IID_IDirectInput8, pDirectInput);

Right now, you basically have half of both, and so your compiler is treating the parameters of the function call as constants because it doesn't have them correctly predefined.