It seems like you're facing a common issue with graphics card compatibility or driver conflicts. Here are a few steps you can take to troubleshoot and potentially resolve the problem: 1. Driver Reinstallation: - Start by completely uninstalling the current graphics card drivers in Safe Mode. You can do this through the Device Manager. - Download the latest drivers for your GeForce GTX 260 from the official NVIDIA website. - Install the downloaded drivers in normal mode after a clean uninstallation. 2. BIOS Update: - Check if there is a newer BIOS version available for your Asus PT6 Deluxe v2 motherboard. Sometimes BIOS updates can improve system stability and compatibility with new hardware like graphics cards. 3. Power Supply Check: - Ensure that your PSU (ABS Tagan BZ Series BZ900) is providing enough power to the system, especially to the graphics card. Insufficient power can cause stability issues. 4. Hardware Check: - Verify that the graphics card is properly seated in the PCIe slot and that all power connectors are securely attached. - Check for any physical damage on the graphics card and clean the contacts if necessary. 5. Compatibility Mode: - Try installing the graphics card drivers in compatibility mode. Right-click on the driver installer, go to Properties, and select compatibility mode for an older version of Windows if needed. 6. Windows Update: - Ensure that your Windows 7 OS is fully up to date. Sometimes, system updates can also resolve compatibility issues. 7. Event Viewer: - Check the Windows Event Viewer for any error messages or logs that might provide more insight into what is causing the system to lock up. 8. Alternative GPU: - If possible, try using a different graphics card in your system to see if the issue persists. This can help determine if the problem is specifically related to the GeForce GTX 260. By following these steps, you should be able to diagnose the issue causing the lockups with your new graphics card on your Windows 7 system. If the issue persists, feel free to provide more details for further assistance.