How to solve the error code 0x800705b4: Windows Update encountered an unknown error in Windows Server 2003 R2

There are several steps you can take to solve the error code 0x800705b4 in Windows Server 2003 R2:

1. Restart the Windows Update service: Go to Start > Run, type "services.msc" and press Enter. Locate the Windows Update service, right-click on it and select "Restart". Wait for the service to restart and try running Windows Update again.
2. Check your internet connection: Make sure your internet connection is stable and working properly. If you are using a proxy server, make sure it is configured correctly.
3. Disable antivirus software: Sometimes antivirus software can interfere with Windows Update. Try disabling your antivirus software temporarily and see if that resolves the issue.
4. Run the Windows Update troubleshooter: Go to Start > Control Panel > Troubleshooting > System and Security > Fix problems with Windows Update. Follow the prompts to run the troubleshooter and see if it can identify and fix the issue.
5. Manually download and install updates: If all else fails, you can try manually downloading and installing the updates that are causing the error. Go to the Microsoft Update Catalog website, search for the updates you need, download them and install them manually.