Install Product Key Windows 7 - Edit Article How to Reinstall Windows 7. In this Article: Performing a Startup Repair Performing a System Restore Performing a Clean Install Using the Recovery Console Community Q&A References Reinstalling Windows 7 every 6 to 12 months--as opposed to never reinstalling--can keep your computer running as smoothly as possible.. The Windows Registry is a hierarchical database that stores low-level settings for the Microsoft Windows operating system and for applications that opt to use the registry. The kernel, device drivers, services, Security Accounts Manager, and user interface can all use the registry. The registry also allows access to counters for profiling system performance..