Drive D to Lenovo G580 Laptop Not Accessible!

My Drive D to Lenovo G580 laptop cannot be accessed. My laptop runs Windows 7 ultimate and whenever I try to open drive D of my laptop, I get this error message "D: is not accessible. Access denied" I have accessed my computer's drive through the administrator account and I don't understand why this is so. All other drives can be accessed except the local disk D. Please is there someone who had experienced a similar problem to bail me out??
