Hidden fields and continuous spinning (JQuery version conflict)

I was trying to create hidden fields in my contact form.
To do this I’ve found this solution to be the only one working:

-ADD JQuery 1.7.1
I added a folder in “js” folder of my child-theme and created jquery-1.7.1.min.js with this code:
http://pastebin.com/tGET58N2

-ADD .js with the hiding function
I added hidefieldScript.js to my “js” folder, to hide some fields unless “Milano” was selected, with this code:
http://pastebin.com/XFxchmvH

-CALL JQuery and the script
I called both in function.php from WordPress child-theme editor using this code:

<script type="text/javascript" src="<?php echo get_stylesheet_directory_uri(); ?>/js/1.7.1/jquery-1.7.1.min.js"></script>
<script type="text/javascript" src="<?php echo get_stylesheet_directory_uri(); ?>/js/hidefieldsScript.js"></script>

The hiding script hide the stuff I wanted to be hidden, but the JQuery version have a conflict with the old one and that mess everything up with mi Contact Forms.

I cannot submit the form and I have the continuous spinning loading near the submit button of my form.

How can I resolve this conflict?
I would like to have both the feature: “hidden fields” and “contact form” so I don’t want to just disable something.

Thank you!!

https://wordpress.org/plugins/contact-form-7/