To load Sibelius 5.1 onto your new Windows 10 laptop, you can follow these steps:
1. Insert the Sibelius 5.1 disc into your laptop's CD/DVD drive.
2. Open the disc and run the setup/installation file.
3. Follow the on-screen instructions to complete the installation of Sibelius 5.1 on your new Windows 10 laptop.
4. Once the installation is finished, you can launch Sibelius 5.1.
5. To access your .sib files, connect your external HDD to the new laptop and browse for the files within Sibelius.
6. You can open, edit, and work with your .sib files as you did on your old laptop.
Remember to use your Sibelius 5.1 serial number starting SCEP 500 followed by 12 numbers when prompted during the installation process.