It seems like you are encountering an issue when installing Windows 7 on a computer that previously had Windows XP Professional installed. The problem arises after the installation process reaches the stage where it says "Preparing your computer for first time use" and then reboots, leading to a halt at the "Verifying DMI Pool Data" message. Here are a few steps you can take to troubleshoot this issue: 1. Check Boot Order in BIOS: - Ensure that the boot order in the BIOS is correctly set to boot from the hard drive where Windows 7 is being installed. Sometimes, the system might be trying to boot from a different device causing the issue. 2. Reset BIOS Settings: - You mentioned that you reset the BIOS, which is a good step. Make sure that the BIOS settings are back to default or optimized settings to prevent any conflicts that may be causing the installation issue. 3. Remove Peripherals: - Disconnect all unnecessary peripherals such as external hard drives, USB drives, and additional expansion cards. Sometimes conflicts with external devices can lead to installation issues. 4. Check Installation Media: - Verify the integrity of the Windows 7 installation media created with UltraISO. It's possible that the installation process is failing due to a corrupted or incomplete installation disk. 5. Try Different Installation Media: - If possible, create another Windows 7 installation disk using a different tool or method to rule out any issues with the current installation media. 6. Update BIOS: - Check if there are any BIOS updates available for your motherboard. Updating the BIOS to the latest version can sometimes resolve compatibility issues during installation. 7. Compatibility Check: - Ensure that your hardware components are compatible with Windows 7. Check the manufacturer's website for any compatibility issues or driver updates required for Windows 7. 8. Hard Drive Issues: - Run a diagnostic test on the hard drive to check for any potential issues that could be causing the installation problem. Faulty sectors or malfunctioning drives can lead to installation failures. By following these steps, you may be able to diagnose and resolve the issue you are facing with the Windows 7 installation on your computer. If the problem persists, further troubleshooting or seeking professional help may be necessary.