how to run applacation on the machine without qt,msvc2005

I have installed vc2005,and the applacation can run,I do not know why.
1. I use debug Qt dll to generate my release Dll,Has it to do with it?
2.During install the vc2005,maybe change sth in the register table,Has it to do with it?

Did you run the vcredist bundle on the target machine or did you only copy it there?

No,I have installed it.After install it,Do I need to configure sth?

0. build your app and put all needed dlls with executable.
1. install vcredist on dest machine.
2. copy your app with dlls on dest machine.
3. run your app.
that's all what you need to do.

You must not use any debug dlls in your release application.

If I want to install my software on the user machine(without vc++2005),Must I install vcredist first?

yes, you must install it.

How do I know that vcredist has been installed sucessfully?
When I install it on a machine (winxp),the progress bar disappeared soon,and I did not know where did I install it?(C: or D:or...)?

it is installed in Windows directory.

Thank u for ur answer.
I did as follows:
1.In the msvc2005 ,I create a 'install and deployment' project,and add all my application to the project.
2.I install vcredist first on the target machine.
3.I install my application on the target machine.
Now, I want to know,how not to install vcredist addationally,that is,when I create a ''install and deploymentproject',how to integrate vcredist into it?