It seems like you're experiencing authentication issues on Windows 7 after upgrading from Vista. Authentication problems can be quite frustrating, especially when they occur inconsistently. Here are some steps you can take to troubleshoot and potentially resolve this issue: 1. Check Network Settings: - Ensure that your network settings are correctly configured. Check if your network adapter drivers are up to date. 2. Check Domain Settings: - Verify that the domain settings are correctly configured. Make sure the computer is properly joined to the domain. 3. Antivirus Software: - Temporarily disable the antivirus software to see if it might be causing the authentication issues. Sometimes security software can interfere...