If you're using any security software (such as antivirus, firewall), please make sure to follow the instructions given in the
Security Software Configuration Guide to see if that helps. If it doesn't click your Windows Start button then type the following command:
Event Viewer
In the top left section, expand "Windows Logs" and click on "Application". Look for recent errors relating to PostgreSQL in the top center pane - click on it when you find one and tell us what the error text says in the bottom center section.