If you face error on re-installation of OpenERP or pgAdmin, then you need to add the port 5432 for Postgres in Inbound and Outbound Rules.
Follow these step given below:-

Step1- Go to Control panel/System and Security/Windows Firewall and select Allow a program or a feature through Windows Firewall on the left menu.
Step2- Go to new rule in Inbound Rules and create, a wizard will appear.
Step3- Select Port as Rule Type, select TCP and specify the port as 5432 click next.
Step4- Select Allow Connection and click next.
Step5- Select the domains you want, here all.
Step6- Give it a meaningful or recognizable name and Finish.
Step7- Similarly create the outbound rule for the same port.
Step8- Check if all the firewalls are Off.
Step9- Restart PgAdmin and try to connect again.