Error in SQLserver connection on other PC

Question

Hi all...
I doing the pro  on c# contain sql database 2005, and it worked 100% when  I run on my PC.
And it show error message when I run it on other PC.

This is Connection statement I used:

 using System.Data.SqlClient;

SqlConnection cn = new SqlConnection(@"Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\Database1.mdf;Integrated Security=True;User Instance=True");

And I want to know if other PC, must install SQLserver or dotnet to run Pro.

Regards...