You need to provide additional information. Are you logging in to a domain? Do you have administrator rights to your local computer? Are there others that will logon to your computer? IS local logon [logon to this computer] authorized? There is a difference between logon local and logon through a domain account. This determines where the authority for this action is controlled.
IF you have local administrator rights then you can use NTFS permissions to limit access. BUT, usually any administrator will still be able to have access or at least take ownership then have rights.