It seems like you are encountering an error message (Error code: 0xC0000005) when trying to install Windows 7 BETA on your system running Windows Vista SP2. This error is usually related to memory access violations, indicating that the installer encountered an issue accessing a specific memory address during the installation process. Here are some potential reasons for this error and steps you can take to troubleshoot the issue: 1. Corrupted Installation Files: - Ensure that the Windows 7 BETA installation files you are using are not corrupted. Try downloading a fresh copy of the installation files and creating a new installation media. 2. Compatibility Issues: - Windows 7 BETA might have compatibility issues with certain hardware configurations. Although your system meets the minimum requirements, there could still be compatibility issues. - Check if your hardware components (such as the graphics card, network adapters, etc.) have Windows 7 drivers available. If not, it could lead to installation errors. 3. RAM Issues: - The error code 0xC0000005 can sometimes indicate issues with RAM. Ensure that your RAM modules are functioning correctly. - Try running a memory diagnostic test to check for any potential RAM issues. 4. BIOS Settings: - Sometimes, incorrect BIOS settings can cause installation errors. Make sure your BIOS settings are configured correctly for the installation process. 5. Hardware Issues: - In some cases, hardware issues can lead to installation errors. Check for any hardware problems, such as a failing hard drive or other components. 6. Third-Party Software Interference: - Disable any third-party antivirus or security software during the installation process. Sometimes, these programs can interfere with the installation. 7. Clean Install: - Consider performing a clean installation of Windows 7 BETA instead of upgrading from Windows Vista. This can help avoid potential conflicts between the two operating systems. Try addressing these points to see if you can resolve the installation error. If the issue persists, provide more details about your installation process, any specific error messages, or any other relevant details for further assistance.