At the 'Welcome to Setup' screen, press Enter. The R (repair) option takes you to the Recovery Module, which is useful if Windows won't boot, but it's no help with a reinstallation. Soon you'll be told that there's already a Windows installation on the computer. Press r for a repair reinstall or Esc to begin a complete, destructive one. For a complete restore, select your C: partition and press Enter. When you get the warning that says an operating system is on that partition, press c. When you are asked your partition preference, select Leave the current file system intact (no changes). When you're told that a Windows folder (or Winnt folder for Windows 2000) already exists, press l ('ell') to delete it and create a new one. Follow the series of prompts. When the installation program asks for your name, enter temp.
Once the installation is complete, your system will reboot into Windows, and you'll be logged on as user Temp. If the screen is difficult to read, reinstall your graphics card driver.