Question: I have installed Drush-5.4-2012-06-04-Installer-v1.0.18.msi in the location C:\ProgramData\Drush by default. I run the program and moved to drupal working directory.

When I type drush it is showing "drush is not recognized as an internal or external command " error. Do I need to configure anything before run? Please help.

Answer: 
You need to set the path variable :

* right click on **computer**
* go to **properties**
* click **advanced system settings** then
* click on **environment variable**, then
* find the variable **path**
* and edit it

add this to end of the variable value **C:ProgramData\Propeople\Drush** and restart the drush, It should work.
For Drupal, you need to run `composer require drush/drush` command from the root project folder