It seems like you're facing an issue with the brightness settings on your Dell Vostro 1400 laptop running Windows 7, particularly when using the battery. Here are some steps you can try to address this problem:
1. Update Graphics Drivers: Outdated graphics drivers can sometimes cause brightness issues. Visit the Dell support website, enter your laptop's model (Vostro 1400), and download the latest graphics drivers for Windows 7.
2. Power Options:
- Adjust Brightness: Go to Control Panel > Power Options. Select your current power plan and click on "Change plan settings." Ensure that the brightness setting is appropriately adjusted for both battery and AC power modes.
- Advanced Power Settings: Click on "Change advanced power settings" in the Power Options window. Check the settings under the display section to make sure that the display brightness is optimized for battery use.
3. BIOS Settings:
- Restart your laptop and enter the BIOS settings by pressing a specific key (usually F2 or Del) during boot.
- Look for any power management settings related to display brightness or battery optimization. Make sure they are configured correctly.
4. Battery Health: If the laptop battery is old or not functioning correctly, it might not be supplying enough power, affecting the brightness. Consider replacing the battery if it's old.
5. Check for Updates: Ensure that your Windows 7 operating system is up to date with all the latest updates. Sometimes, updates contain fixes for such issues.
6. Third-Party Tools: You can also consider using third-party software that allows fine-tuning of brightness settings beyond what the default Windows settings offer.
7. Hardware Check: If none of the software-based solutions work, there might be a hardware issue with the laptop's display or inverter that is affecting the brightness. In such cases, it's advisable to contact Dell support for further assistance.
Try these steps and see if they help resolve the brightness issue when using your Dell Vostro 1400 on battery power. Let me know if you need further assistance or if you have any other questions!