Post installation

Hi , i am runing a druapl site for a big school campus and as users deamend more fleabilaty i need to use the organic group module, but each time i enable the module on admin/modules the MySql+CPU load are jumping to 100% utilization so i have to restart apache and disable the module ASAP.
after disabling the module all is back to normal.

is there a way / variable to check if the logged in user is an admin or moderator or any kind of role?

I'd like to show the loginscreen only to admins/moderators...

I've created an 'event categroy' menu which is populated with terms like 'club,' 'bar,' 'tattoo' etc. using the category module and category menu.

I have used administration>>blocks to set this menu to appear on specific nodes. This works fine.

But how do I set this menu to appear on any node that has a certain categroy, like, for example, 'club?' In other words, is it possible to link this menu to a category term so that anytime a user accesses a node with that term the menu item will appear?

If i want to learn how to be better at drupal, by understanding the code what do i do? DO i just have to learn PHP and MySQL? Or are there also drupal manuals as well?

Basically my question is, what steps does a newbie have to take to learn to program for drupal? Any answer would be greatly appreciated.

Within the design of the frontpage I tried to implement something like this:

{ HEADER }

[ STICKY TEASER: node 15 ]
[ TABLE-LIKE TEASER: node 14 ] (take a look: http://tinyurl.com/tuhgk)
[ NORMAL TEASER: node 75 ]
[ NORMAL TEASER: node 32 ]
etc...

{ FOOTER }

I got a "Fatal error: Call to undefined function module_exists()... error message when I tried to enable and make as default the Garland theme which I added to the Themes directory of a 4.7 installation. The referenced line is a function calling for the color module which I forgot to also install so I did but I'm still getting the error message. I have cleared the cache in the database and have tried reentering via /admin/ and /user?destination=user but I keep getting the same error message. What should I do to log back in?