I have created web to lead form. if lead is genearated from web to lead form then checkbox filed  on the lead object will be checked and processs builder  will send mail to lead owner. My requirement is if the lead is generated from system then process builder should not fire any mail. ?I have written this code. in which i have added this statement 
<input type="hidden" id="00N3600000OxAnG" name="00N3600000OxAnG" checkbox="true" value="1" />
but still if lead is created from system then also process builder send mail to the lead owner. 


<META HTTP-EQUIV="Content-type" CONTENT="text/html; charset=UTF-8"/>
<aside class="col-sm-4">
<section class="request-quote-wrap request-quote-desktop">
<section class="request-quote-wrap">
<h2>Request a Quote</h2>
<section class="request-quote-inner">
<form id="enquiryFrm" action="https://na30.salesforce.com/servlet/servlet.WebToLead?encoding=UTF-8" method="post">
<input type="hidden" name="oid" value="00D36000000Ymbt"/> <input type="hidden" name="retURL" value="http://aress.com/thank-you.html#"/> <input type="hidden" id="00N3600000OxAnG" name="00N3600000OxAnG" checkbox="true" value="1" />
<section class="form-row" style="color:red; font-size:11px;">All fields are mandatory </section>
<section class="form-row"> <label for="first_name">First Name:</label>
<section>
</section><input class="textfld" id="first_name" maxlength="40" name="first_name" size="20" type="text" />
</section> <section class="form-row">
<label for="last_name">Last Name:</label>
<section><input class="textfld" id="last_name" maxlength="80" name="last_name" size="20" type="text" />
</section> </section>
<section class="form-row">
<label for="email">Email:</label>
<section><input class="textfld" id="email" maxlength="80" name="email" size="20" type="text" /> </section> <section class="form-row">
<label for="phone">Phone:</label>
<section><input class="textfld" id="phone" maxlength="40" name="phone" size="20" type="text" /> </section>
</section> <section class="form-row"> <label>Your Preferred Location:</label>
<section class="select-outer"> <select class="select" id="00N3600000OwUK8" name="00N3600000OwUK8" title="Your Preffered Location">
<option value="">Please select</option> <option value="USA">USA</option>
<option value="UK">UK</option> <option value="India">India</option>
<option value="Other">Other</option> </select> </section> </section>
<section class="form-row"> <label> Message: </label> <section>
<textarea class="textarea-fld" aria-labelledby="00N3600000OwJ3B_pcl" id="00N3600000OwJ3B" name="00N3600000OwJ3B" rows="3" type="text" wrap="soft"> </textarea> </section>
</section> <section> <input type="submit" name="submit" value="Submit" class="orange-btn radius"/> </section> </section> </form> </section> </section> </section> </aside> </section>
</section> </section> </section>