Each time i try to open the data base in the server explorer the following error occurs.

"Unable to open the physical file "C:\PROJECT\Site\App_Data\PlanetWrox.mdf". Operating system error 5: "5(Access is denied.)".
An attempt to attach an auto-named database for file C:\PROJECT\Site\App_Data\PlanetWrox.mdf failed. A database with the same name exists, or specified file cannot be opened, or it is located on UNC share."