Connecting Sql Server 2005 From ASP?

Hi
We are planning to move over to SQL Server 2005 in near future.

At the moment Website is on a seperate server then the Database.
OS for both the server is Window 2003 and currently our data is on SQL
Server 2000(on which everything works fine).

Part of the testing process we tried to connect our website on SQL 2005
and it does not work at all.

I get this

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ADODB.Connection error '800a0e7a'
Provider cannot be found. It may not be properly installed.

When i use following connection string
"Provider=SQLNCLI;Server=127.0.0.1;Database=dbName;UID=UserName;PWD=UserPassword;"

(Above string has fixed problem for few people- googled it, but not for
me.)
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This is the message i get for all the following connectiong string

Microsoft OLE DB Provider for SQL Server error '80004005'

[DBNETLIB][ConnectionOpen (Connect()).]SQL Server does not exist or
access denied.

1) - "Provider=SQLOLEDB.1;Password=UserPassword;Persist Security
Info=True;User ID=UserName;Initial Catalog=ABC;Data
Source=XXX.XX.X.XX,1433"

2) - "Provider=sqloledb;Data Source=XXX.XX.X.XX,1433;Network
Library=DBMSSOCN;Initial Catalog=ABC;User
ID=UserName;Password=UserPassword"

3) - "Provider=SQLOLEDB.1;Persist Security Info=True;User
ID=UserName;Initial Catalog=ABC;Data Source = ServerNameSQLInstance"

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I tried connecting to SQL Server 2005 through our system developed in
VB.Net 2003 and it works fine and here is the Connection String :

"Data Source=ServerNameSQLInstance;Initial Catalog=ABC;Persist
Security Info=False;user id=UserName;password=UserPassword"
Then i downloaded SQL Native Client and installed on the web server.

I looked in SAC Tool and "Local and Remote Connection" and "Using Both
TCP/IP and Named Pipes" options are selected. I have checked SQL
Browser service is running.

Now when i use this string

"Provider=SQLNCLI;Server=127.0.0.1;Database=DBName;UID=UserName;PWD=UserPassword;"

i get

Microsoft SQL Native Client error '80040e4d'

Login failed for user 'UserName'.
I have created this user and this user has proper permission to access
the database i need.

I would really appreciate any help as this is driving me crazy.
Mits