Database conn

I have downloaded some code on how to upload images to a sql database and I am getting
this error message

"SQL Server does not exist or access denied.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.Data.SqlClient.SqlException: SQL Server does not exist or access denied."

I have opened Enterprise Manager and made sure I was a "user" and everything seems to be ok there.
The connection string looks like this
"server=localhost;uid=sa;pwd=;database=ImageUpload"
Could anyone give me an idea on what to check or try next

Thanksu can try replacing 'localhost' with the ip address
use ipconfig command to know abt ip addr|||What kind of authentication you used? SQL Server authentication or windows integrated?

Try windows integrated authentication.