Since this is a Dell I am guessing that you have some flavor of Windows for an operating system. If you have your paper settings correct, it sounds like you are running out of memory for your print job since you are not saying it prints 2/3 of a page and the next page is blank.
Go to your control panel. Choose classic view. Double left click the printers and faxes icon. The widow will open and show you all the printers and faxes you have installed. Right click this printer and from the menu that pops up choose properties. Go to the advanced tab. Make sure that "Spool print documents...." is chosen. If you have changed any settings left click the apply button on the bottom right of the properties window. If the A4 paper is not what you mainly use you will have to select it each time you go to print with that paper. If the only paper you print on is A4 then go to the general tap left click on the printing preferences button. Left click the advanced button and make sure that the A4 is your default paper. Left click the ok button. If you have changed any settings left click the apply button on the bottom right of the properties window. Now click ok, which will bring you back to the general tab. Left click on the print test page button. See if It prints properly. Please let us know the results of doing this.