With Windows 10, Microsoft seems to have disabled System Restore by default — at least on some PCs. System Restore has been around since Windows ME, creating snapshots of system files you can restore if a problem occurs.
BitLocker disk encryption normally requires a TPM on Windows. Microsoft’s EFS encryption can never use a TPM. The new “device encryption” feature on Windows 10 and 8.1 also requires a modern TPM, which is why it’s only enabled on new hardware. But what is a TPM?