oops, I wanted to delete this post, but the other post got deleted.
I'm gonna share what I learned and what I did with the xml
1. I need to edit some xml on the dev_flash to modify the xmb. I did it through ftp. To be able to use ftp on ps3, I installed Webman Mod.
2. To be able to write the edited xml back to dev_flash, I enable the dev_blind in the Webman Mod. Then the dev_flash is mounted as dev_blind which is writable. Any modification made to dev_blind is actually made to dev_flash. Be very careful of any modification you made to dev_blind because you could brick your ps3 if you do something wrong.
3. I renamed the xml I want to modify to bak files, then I uploaded the xml I edited.
4. Reboot ps3, the Cobra Menu, Webman Setup Menu, Game Data and Game Saves are gone.
It seems I can't upload files, so I will just paste the code here.
Just comment the following code out. The Menus will disappear and kids won't accidently delete files or delete game saves.
hide Cobra Menu
\dev_blind\vsh\explorer\xmb\
category_network.xml
<!-- <Query
class="type:x-xmb/folder-pixmap"
key="cfw_settings"
src="#seg_cfw_settings"
/> -->
category_network_tool2.xml
<!-- <Query
class="type:x-xmb/folder-pixmap"
key="seg_cfw_settings"
src="xmb://localhost/%flash/xmb/category_network.xml#seg_cfw_settings"
/> -->
Hide Webman Setup Menu, Game Data and Game Saves
\dev_blind\vsh\explorer\xmb\
category_game.xml
<!-- <Query
class="type:x-xmb/folder-pixmap"
key="seg_gamedata"
src="#seg_gamedata"
/> -->
<!-- <Query
class="type:x-xmb/folder-pixmap"
key="seg_sdps3"
src="#seg_sdps3"
/> -->
<!-- <Query
class="type:x-xmb/folder-pixmap"
key="seg_gamedebug"
src="#seg_gamedebug"
/> -->
<!-- <Query
class="type:x-xmb/folder-pixmap"
key="seg_gamedata"
src="#seg_gamedata"
/> -->
<!-- <Query
class="type:x-xmb/folder-pixmap"
key="seg_sdps3"
src="#seg_sdps3"
/> -->
category_game_tool2.xml
<!-- <Query
class="type:x-xmb/folder-pixmap"
key="seg_gamedata"
src="xmb://localhost/%flash/xmb/category_game.xml#seg_gamedata"
/> -->
<!-- <Query
class="type:x-xmb/folder-pixmap"
key="seg_sdps3"
attr="seg_sdps3"
src="xmb://localhost/%flash/xmb/category_game.xml#seg_sdps3"
/> -->
<!-- <Query
class="type:x-xmb/folder-pixmap"
key="seg_gamedebug"
src="#seg_gamedebug"
/> -->
<!-- <Query
class="type:x-xmb/folder-pixmap"
key="seg_gamedata"
src="xmb://localhost/%flash/xmb/category_game.xml#seg_gamedata"
/> -->
<!-- <Query
class="type:x-xmb/folder-pixmap"
key="seg_sdps3"
attr="seg_sdps3"
src="xmb://localhost/%flash/xmb/category_game.xml#seg_sdps3"
/> -->
<!-- <Query
class="type:x-xmb/folder-pixmap"
key="seg_gamedebug"
src="#seg_gamedebug"
/> -->
<!-- <Query
class="type:x-xmb/folder-pixmap"
key="seg_gamedata"
src="xmb://localhost/%flash/xmb/category_game.xml#seg_gamedata"
/> -->
<!-- <Query
class="type:x-xmb/folder-pixmap"
key="seg_sdps3"
attr="seg_sdps3"
src="xmb://localhost/%flash/xmb/category_game.xml#seg_sdps3"
/> -->
<!-- <Query
class="type:x-xmb/folder-pixmap"
key="seg_sdps3"
attr="seg_sdps3"
src="xmb://localhost/%flash/xmb/category_game.xml#seg_sdps3"
/> -->
<!-- <Query
class="type:x-xmb/folder-pixmap"
key="seg_sdps3"
attr="seg_sdps3"
src="#seg_sdps3_noicon"
/> -->
\dev_hdd0\xmlhost\game_plugin\
<!--
<P key="title"><>webMAN Setup</></P><P key="info"><>Setup webMAN options</></P><P key="module_name"><>webrender_plugin</></P><P key="child"><>segment</></P>
-->
</T></A><I>
<!--
<Q class="type:x-xmb/folder-pixmap" key="setup" attr="setup" src="xmb://localhost/dev_hdd0//game/XMBMANPLS/USRDIR/FEATURES/webMAN_EN.xml#seg_webman_links_items"/>
-->