While You are trying to install Oracle Database On Windows 2008 R2 or any other Microsoft Os with user not administrator you will get
DIM-00014: Cannot open the Windows NT Service Control Manager. O/S-Error: (OS 5) Access is denied.
Run DBCA as administrator .
Click on start button -> All programs -> Accessories -> right click the command prompt icon > choose run as administrator -> invoke dbca in the commandline or oradim can also be used.