Tested in vbulletin version 5.6.4 works fine

Description:
====================================
Superadmins (from "core/includes/config.php" file) can delete users
but, normal admins can NOT delete users

How to install :
====================================
Follow install instructions

1-) download and open "core/admincp/user.php" file

2-a) find

PHP Code:
print_cp_header($vbphrase['user_manager'], '', $extraheader); 
2-b) replace with

PHP Code:
if ($_REQUEST['do'] == 'remove' AND !in_array($vbulletin->userinfo['userid'], preg_split('#\s*,\s*#s', $vb5_config['SpecialUsers']['superadmins'], -1, PREG_SPLIT_NO_EMPTY))){
    print_cp_header('Access Denied');
}
else{
    print_cp_header($vbphrase['user_manager'], '', $extraheader);
} 
3-a) find
PHP Code:
if ($_REQUEST['do'] == 'remove')
{ 
3-b) add BELOW

PHP Code:
if (!in_array($vbulletin->userinfo['userid'], preg_split('#\s*,\s*#s', $vb5_config['SpecialUsers']['superadmins'], -1, PREG_SPLIT_NO_EMPTY)))
{
    print_table_start();
    print_table_header('Access Denied');
    echo "<td class="alt1" nowrap="nowrap" align="center">You Have No Permission For This Process</td>";
    print_table_footer(2, '', '', 0);
}
else{ 
4-a) find

PHP Code:
// ###################### Start Kill ####################### 
4-b) add ABOVE

PHP Code:
} 
5-) save and upload to ur admincp directory. that's all

Notice: u can edit sentences manuel which re highlighted at ss

How to uninstall:
========================================
It is sufficient to overwrite the "core/admincp/user.php" file on your server with its original.

-----
Mark as installed get support.

for vB4

Attached Files