Question about freezing panes in MS EXcel

I have an existing spreadsheet that has now grown so that it will not fit on the screen in one shot any more. I want to freeze the top two rows so I can see the column titles but I am having a problem. I highlight the necessary cells and when I go to Window>Freeze Panes it freezes the upper left portion of the screen only. So rows 1-18 and columns A-D are frozen instead of the top two rows like what I want to do. I tried opening up a new window and testing to see if the file I have is corrupt and it does the same thing. Any idea as to what is going on?

Select cell A3, and then freeze. I think that will give you what you want.

Similar to what Paul said, here's the info from the help file. Instead of selecting, you can drag the split window to where you want it and then freeze the panes.

I was able to get it to work using Paul's instruction. Using the instructions from the Excel Help it did not work. I normally highlight the row below what I want to freeze and it works just fine. That was not the case this time however. It only worked when I clicked on the first cell on the left below the lines I wanted to freeze which is in the "A3" cell. I don't get what is causing this to happen in only this one file.