TPM is on in the bios and you know full well the laptop has a TPM module.  Yet Windows keeps claiming one doesn’t exist.

Tested on a Dell Latitude E6320.  Using a standard build rolled out via SCCM.

Possible a driver issue.  No security module option appearing in Device Manager.

Go to System Devices in Device Manager and if you see the Broadcom TPM there, if so uninstall and make sure to tick the box that says remove the software, otherwise when you reboot it will just silently reinstall.

Once removed, I rebooted and all was fine.  The proper Security section in Device Manager appeared.  Then Windows 7 was able to Bitlocker the drive.