if the disk has been encrypted, you must enter correct password before you start use it .
1. Click Start > Programs >KernSafe> DiskEncryptor>DiskEncryptor; to start up DiskEncryptor, choose which disk partition you want to use, pitch on it and then Click the 'Unlock' button.

2. Enter correct password

3. After you use the disk, you should be click the 'lock' button to protect it , after that no one can access it without the correct password .