The problem is that all of your checkbox have the same ID "checkNote".
This is a proposed solution
HTML
<table id="tblflex" class="flexCLS" style="display: table;" border="0">
<tbody>
<tr id="row101">
<td align="left">
<div style="text-align: left; width: 40px;">
<input type="checkbox" id="checkNote101" onclick="checkedCall(this);">
</div>
</td>
</tr>
<tr id="row187">
<td align="left">
<div style="text-align: left; width: 40px;">
<input type="checkbox" id="checkNote187" onclick="checkedCall(this);">
</div>
</td>
</tr>
And the JS Code
<script type="text/javascript">
function checkedCall(this) {
if( $(this).is(':checked')){
//$("#tblflex > tr:first").addClass("trSelected");
//$(this).parents('tr:first').addClass('trSelected');
alert('Selected' + $(this).parents('tr:first').attr('id')); //unable to find the ID
}else{
alert('NOTSelected');
//$("#tblflex > tr:first").removeClass("trSelected");
//$(this).parents('tr:first').removeClass('trSelected');
}
}