After installing Windows 8 Pro i cannot play my DVD
s due to application Error E;\ how do i fix this they worked fine with Windows 7 my computer is a HP Pavilliona6334f

You cannot run Windows 8 on that model. HP do not have any Windows 8 drivers for it. That's why some hardware components don't work. HP do not have any Windows 7 drivers for it either, so I guess you must have used Vista drivers as they are the only drivers that HP have for the Pavillion a6334f.
While Vista drivers will often work on Windows 7, they will definitely not work on Windows 8.
You must always check what drivers are available on the PC maker's website before upgrading (or downgrading) the OS.
Did you upgrade over Win 7 or did a clean installation of Win 8 ? If upgrade, you should be able to play DVD disks ( I assume you mean DVD video disk ) on your computer. If clean install, Windows 8 Pro does not come with the necessary codec pack to play DVD movie disks. You must get free Windows Media Center pack ( free till 31st of January, 2013 ). If your DVD drive does not work, then it could be upper-lower filter problem.
CoolGuy
I ddid as you said the HP pavillion will not play on Windows 8 Pro but i downloaded and recieved a product key for Winddows media centre pack & installed it both my internal & external Dvd players work now. I thank you for your input
Thank you for your input. Installing Winddows media centre pack was correct ,Both internal & external Dvd drives work fine
