What errors are you getting?

If you are getting the Operating System error 5(Access is Denied) error, then it is a file permission issue. Go to Run and launch services.msc. Find your SQL services and look at the Log On As field. Make sure that user account has file permissions to the folder where the database resides. I am not a fan of using administrator for running services, but that is my preference.

If your Log On As account is in a domain, make sure you specify the domain name (Domain\LogOnAsUser)