You don't seem to have put in quite the effort required, but I'll help you out anyway - check out this thread, as it is a very common issue; I had this one as well, but I used the search function and found what I needed to fix it.
If that does not solve it, go back and go through the instructions again one more time STEP-BY-STEP - 99% of the time it is one minor thing you have overlooked or assumed you already had, that is messing you up. Then, if the problem persists, come back here and start using the search function, if all of this fails, post a clear, concise detailed report here of what exactly the issue is, with a log =-)