Magento Can't able to login in admin

Some time After the installation of magento we can't able to login in admin and we stuck that we have not installed Properly generically while installing some of the permission is required which is not available and so we need to edit one file

Magneto add Manufacture in grid Column for Admin

Add the brand/manufacture in grid for admin
Just open the file \app\code\core\Mage\Adminhtml\Block\Catalog\Product\grid.php and
Paste in local folder app\code\local\Mage\Adminhtml\Block\Catalog\Product
and add the below code in  _prepareColumns( ) function

Magento Change admin URL

For security reason now it became useful to change the url of the admin
Follow the steps to change the url
Open app/etc/local.xml
Find the following
<admin>
    <routers>
            <adminhtml>
                <args>
                    <frontName><![CDATA[admin]]></frontName>
                </args>
            </adminhtml>
        </routers>
</admin>

Change
<frontName><![CDATA[admin]]></frontName>
to your name which u have think

 Like below:
<frontName><![CDATA[editname]]></frontName>

hope this will help you

Magento admin problem

Many times it happen developer can't able to Login into the Admin even though they have entered the correct username and password
so here is the solution

1) Use 127.0.0.1 instead of localhost in your url, i.e. using

http://127.0.0.1/magento/index.php/admin instead of
http://localhost/magento/index.php/admin . we  think it will not solve our problem.

2) Running on Windows XP, I was suggested to open “host” file from
C:\WINDOWS\system32\drivers\etc and have 127.0.0.1 point to something like magento.localhost

or even 127.0.0.1 point to http://www.localhost.com . But this also didn’t work either.

3) This solution finally helped us out of this problem. The solution was to modify the core

Magento code. Open

app/code/core/Mage/Core/Model/Session/Abstract/Varien.php. Comment out the

lines 80 to 83. The line number may vary according to the Magento version. But these lines

are present somewhere near line 80. You have to comment the comma (,) in line: $this-

>getCookie()->getPath()//,

// set session cookie params
session_set_cookie_params(
$this->getCookie()->getLifetime(),
$this->getCookie()->getPath()//,
//$this->getCookie()->getDomain(),
//$this->getCookie()->isSecure(),
//$this->getCookie()->getHttponly()
);

It will help you