How long does it take to reinstall Windows?
Generally, the reinstall of Windows takes between 1 and 5 hours. However, there is no exact time for how long it can take to install Microsoft Windows and can vary based on the below factors.
Upgrade vs. Full install
A Windows "Upgrade" from a previous installation will take longer than a clean install. Upgrades use all the current data in the current operating system, instead of just replacing all the files. Many are upgraded along with the Installation to keep all your current settings and data.
For many of the hardware devices installed and connected to your computer, additional drivers and software will need to be installed. Although Windows can detect and install the software required for many hardware devices, which can increase the overall installation time, it's possible that not all hardware will be detected. It'll be up to the user after the installation of Windows to install the remaining software and drivers for their hardware.
Finally, you'll need to install all available Windows updates after installing Windows. For versions of Windows that have been out for several years, there can be dozens of additional software updates and service packs that need to be installed to finalize the Windows installation. Depending on the speed of your Internet connection, how many updates need to be installed, and how many times your computer needs to be restarted after the updates, can cause this final step to add an additional one or more hours to the initial install time.