If you are looking to clean boot your PC running Windows 7 Home Premium but don't have the password, you may encounter some challenges. A clean boot can help in troubleshooting issues related to software conflicts or system errors. Here's how you can proceed:

1. Insert the Windows 7 installation disc and restart your computer.
2. Press any key when prompted to boot from the CD/DVD.
3. Select your language preferences and click 'Next'.
4. Click on 'Repair your computer'.
5. Choose the operating system to repair and select 'Next'.
6. Click on 'Command Prompt'.
7. Once the Command Prompt window opens, type 'BCDEDIT /SET {DEFAULT} BOOTMENUPOLICY LEGACY' and press 'Enter'.
8. Close the Command Prompt and restart your computer.
9. Press the F8 key repeatedly during startup to access the Advanced Boot Options menu.
10. Choose 'Safe Mode' or 'Safe Mode with Networking' as per your requirement.
11. Your PC will now boot in a clean state without requiring the password.

It's important to note that performing a clean boot without the password may not be a straightforward process and could potentially cause data loss or system instability. Proceed with caution and consider seeking professional assistance if needed.