Need more info, what won't the HP play?
Does the player have a model number?
None of my HD DVDS will play on my HP Computer that has a Toshiba HD DVD Drive in int. I used the computer scan tool to see if the HD DVD PLayer works and it says it is working fine. However when I put any and even brand new HD DVDS in the HD Drive it says "Format not supported", my computer is a model nymber m8100y HP, I have downloaded the last and latest drivers for it and still odesnt play my HD DVDS, I even uninstalled it and reinstalled it and the same luck, it still reads "Format not supported"..... Thanks for your help, looking forward to having positive results from your advice!