How to have .net lauch a condition when installing

To add a launch condition for YourApplicaiton

Select the deployment project in Solution Explorer. On the View menu, choose Editor, Launch Conditions.Select the Requirements on Target Machine node. On the Action menu, choose Add Registry Launch Condition.
Select the Search for RegistryEntry1 node. In the Properties window, select the
RegKey property and enter Software\MyApp.
and then u can put some conidtion over there

Oops i forgot one thing

Select the Root property and enter vsdrrHKLM.
Select the Value property and enter AppName.
Select the Property property and enter MYAPPSEARCH.

In the Launch Conditions Editor, select the Condition1 node. In the Properties window, select the Condition property and enter MYAPPSEARCH=“Jawad”.
Select the Message property and enter MyApp is already installed on this O/S.