I dont know why, one day , I cannot see 2 site colleciont information in central admin, the origianl site collection locate the web application 80 but now suddenly change the central admn web applcation, I want to want to back to the web application port 80

Hi, Are you attempting to move site collections back to port 80 or an entire web application to port 80? If you want to move the site collection, you will need to export it first with STSADM -o export and import it to the new web application. If it just the web application and you want to change its port, you can do it the quick way(no recommended for long term use) by updating IIS and the port number and then going into Central Admin and updating the Alternate Access Mappings. Regards, Savoeurn Va Microsoft Online Community Support