Reinstalling replaces the operating system on your VPS with a new one. You can do it yourself from the server's page, from a ready template or from an ISO image. The IP address and the plan stay the same.
A reinstall deletes all data on the server, and this can't be undone. Copy anything you want to keep before you start.
How to reinstall from a template
Step 1: Open your server's page.
Go to My servers and click Manage next to the server.
Step 2: Open Reinstallation.
In the menu on the left, under Service Management, click Reinstallation.
Step 3: Choose a template.
On the KVM Templates tab, click the operating system or app you want and confirm.
The server is offline while it reinstalls, usually for a few minutes. It starts again by itself with the new system.
Windows Server restarts a few times during setup. Wait up to 10 minutes before you connect with Remote Desktop.
How to install from an ISO image
The ISO Images tab starts an installer instead of a ready system. You finish the installation yourself in noVNC Console, the server's own screen in your browser. Choose it only if you need a system or a disk layout that the templates don't offer.
The steps are in Install your VPS from an ISO image.
After the reinstall
Your login details are in the Information block on the server's page.
When you connect with SSH again, it warns that the host key changed. That's expected after a reinstall. See Fix SSH host key verification failed error.
Task History shows the reinstall as four tasks: Stop, Destroy, Resize and Start. See Task history in the LumaDock control panel.
Settings inside the old system are gone, including its own firewall. Set them up again on the new one.