Hi
From your template manager — >JA Univeristy – Default –>Options Tab –>Layouts Tab –> Default Layout –Clone and call it newhome
After created edit it
<blocks name="top" style="xhtml">
<block name="absolute" type="modules" style="raw">absolute</block>
<block name="top-panel" type="modules" style="raw" main-inner="1">top-panel</block>
<block name="header" type="header" main-inner="1"></block>
<block name="mainnav" type="mainnav" main-inner="1"></block>
<block name="cpanel" type="usertools/cpanel"></block>
<block name="masshead" style="raw" no-main="1">masshead</block>
<block name="slideshow" style="raw">slideshow</block>
<block name="topsl" type="spotlight">user1, user2, user3, user4</block>
<block name="topsl1" type="spotlight">user5, user6, user7, user8</block>
<block name="topsl2" type="spotlight">user9, user10, user11, user12</block>
</blocks>
Remove the block portion in RED and save it
Go to Profiles Tab and choose the HOME profile
Under Layout Settings –> Desktop Layout assign your new layout (newhome) and save
Now you have the Home page without the mainnav
Regards