Windows actually does use the TPM to improve security. Bitlocker in TPM mode can prevent tampering with the operating system even with full direct access to the

Windows actually does use the TPM to improve security. Bitlocker in TPM mode can prevent tampering with the operating system even with full direct access to the hardware, and Vista+Bitlocker+TPM is the only system I know of that provides that level of protection for consumer-level hardware.