Hi neotrix !
You can do it following some steps below :
1.Open index.php file in templates/ja_mageia folder, find following code section at about line 225 :
<?php if ($this->countModules('left')) { ?>
<!-- BEGIN: LEFT COLUMN -->
<div id="ja-col1">
<div class="ja-innerpad">
<?php if ($JAconfig->ja_menutype == 1 && $jamenu->hasSubMenu (1)) {
echo '<div id="ja-subnavcol" class="moduletable">';
echo '<h3>'.$jamenu->getParentText (1).'</h3>';
$jamenu->genMenu (1);
echo '</div>';
} ?>
<jdoc:include type="modules" name="left" style="xhtml" />
</div>
</div><br />
<!-- END: LEFT COLUMN -->
<?php } ?>
remove it.
2. Open template_css.css file in templates/ja_mageia/css folder, find following code section at about line 770 :
#ja-mainbody, #ja-mainbody-fr {
float:right;
width:77%;
}
change to :
#ja-mainbody, #ja-mainbody-fr {
float:right;
width:100%;
}
3. Find following code section at about line 1115 :
#ja-col2 {
float:right;
overflow:hidden;
width:30%;
}
change to :
#ja-col2 {
float:right;
overflow:hidden;
width:20%;
}
4. find following code section at about line 750 :
#ja-containerwrap, #ja-containerwrap-fr {
background:transparent url(../images/mainwrap-bg.gif) repeat-y scroll 23% 50%;
}
change to :
#ja-containerwrap, #ja-containerwrap-fr {
}