How can you return your system to a configuration from three weeks ago?

Three weeks ago, you installed a new piece of hardware that you suspect has been intermittently causing system errors. Unfortunately, you’re not 100% sure that the new hardware is the issue, or if it may be related to a new video driver that was installed after the installation of the new hardware. What Windows feature would allow you to go “back in time” and change your system configuration to be exactly as it was three weeks ago, prior to any of these new installations?

How should you troubleshoot this startup problem?

Your Windows startup process is crashing with a Windows Stop error before you can get a login screen. You suspect that a service is crashing the system, but you obviously can’t use your normal login process to disable the service. What is the next best option for ensuring the service is disabled?