"TPM" (Trusted Platform Module) is a specialized chip on your computer's motherboard that provides hardware-based security functions. When installing Windows 11, your computer needs to meet certain hardware requirements, including having TPM 2.0 enabled.

If your old computer doesn't have TPM 2.0, you might need to disable it or bypass the requirement to install Windows 11. Here's a brief overview of how to do it:

1. Access BIOS/UEFI Settings: Restart your computer and enter the BIOS/UEFI settings (usually by pressing a key like F2, F10, or Delete during startup).

2. Find TPM Settings: Navigate to the security or advanced settings section.

3. Disable TPM: Look for an option related to TPM (it might be called Intel Platform Trust Technology or PTT) and disable it.

4. Save and Exit: Save your changes and exit the BIOS/UEFI settings.

Alternatively, you can bypass the TPM requirement by modifying the Windows registry during the installation process. Here's a simplified version of how to do it:

1. Open Command Prompt: During the Windows 11 installation, open the command prompt by pressing Shift + F10.

2. Edit Registry: Type regedit to open the registry editor.

3. Create LabConfig Key: Navigate to HKEY_LOCAL_MACHINESYSTEMSetup and create a new key named LabConfig.

4. Add DWORD Values: Inside the LabConfig key, create two DWORD values named BypassTPMCheck and BypassSecureBootCheck and set their values to 1.

5. Continue Installation: Exit the registry editor and continue with the Windows 11 installation.

These steps should help you install Windows 11 on older hardware that doesn't meet the TPM 2.0 requirement. If you need more detailed instructions or run into any issues, feel free to ask!

https://www.tomshardware.com/how-to/bypass-windows-11-tpm-requirement

https://www.youtube.com/watch?v=q9lq4FcDK4k