One more idea:
Go to your below directory on your machine:
C:\Program Files (x86)\SAP BusinessObjects\SAP BusinessObjects Enterprise XI 4.0\win32_x86\Start Page\en
Take a backup of start.html file (If the below, doesn't work you can put it back)
Open start.html and edit in notepad remove below code and save it , your annoying tab disappears 
<div id="onlinecontent">
<iframe width="100%"
height="1200px" align="center" scrolling="auto" FRAMEBORDER="0" class="resources" id="onlineresourse"></iframe>
<script type="text/javascript">InitializeResourcesTag("onlineresourse")</script>
<script type="text/javascript">SetFrameSource("onlineresourse")</script>
</div>