user register hook form alter not reaching
The naming convention for hooks is:

MODULENAME_hook_name()


So to implement hook_form_alter() in a module called MYMODULE, your function would be defined as:

function MYMODULE_form_alter(&amp;$form, &amp;$form_state, $form_id) {
  // ...
}


Have a look at What is the basic concept behind hooks? for a more detailed explanation.