Not able to connecting to the Sharepoint site

See more:

SharePoint

SharePoint2010

Dear Experts,

Here i am facing a big problem with my sharepoint site.

We are having one Pre-Production server system named SERVER1.
This server having sharepoint and sql server. In this SERVER1,

in IIS

We have main site: Sharepoint-11111( This is my main Web application pool)
For this we have extend site: Sharepoint-xxxxx(using port 443)

Here Localhost and extend website everything working fine.

Then, we are planning to move sql databases and content databases to the other system named SERVER2(This system doesn't have sharepoint).

1.They moved all the sql databases and content database from SERVER1 to the SERVER2.

2.Then, in SERVER1 sharepoint central administration, changed default connecting server from SERVER1 to SERVER2.

Here the site works fine, later we realized that some of the connections still pointing to the SERVEER1.

3.Then they configured in programfiles\sharepoint2010 product configaration wizard-here they configured to connecting to the SERVER2. Here its not configured, they got some errors, may be the SERVER2 dont have sharepoint.

4.finally they are trying to bring back to original state in SERVER1.

For this, they re-configured the share point 2010 product configuration.

this time its configured, but all the virtual directories data get reseted. we have the backup all the virtual directories, so we restored here.

In the SERVER1- localhost(Sharepoint-11111) its worked fine. If we access the Extend site(Sharepoint-xxxxx) from other system using user credentials its not loading.

Finally they restared the SERVER1 system.

After restarting the system, if we trying to access the site from other system its showing the error like

Error:

HTTP/1.1 200 OK
Server: Microsoft-IIS/7.5
Date: Tue, 18 Jun 2013 14:28:34 GMT
Connection: close

Later we checked in IIS the particular web site:Sharepoint-xxxxx its got stopped.
Then we started this site, its not getting started its showing error like that

Error:

"Another site may already be using the same port, site can not be started".

We checked in all IIS websites, not a single website is using 443

We are detached and attached all the databases, no luck.

Kindly help me about this issue.

Any Suggestions please