i have dowloaded a evaluation copy of windows server 2008 r2 os .when i tried to install it ,it is asking me administrator password ,but i have not given any password at the time of installation.why this is happening

Username: administrator, password: Pass@word1 (Administrator account) Try this, this is generally the default credentials for windows evaluation images/.vhds.

When you install Server 2008/2008 R2, it asks you to change the local administrator password when it boots for the first time. Once you set the password initially, it will allow you to continue. -- Mike Burr

If you downloaded the VHD, administrator account is already exists. See the page below: Windows Server 2008 R2 Evaluation Virtual Hard Drive Images for Hyper-V (180 Days) http://www.microsoft.com/downloads/details.aspx?FamilyId=9040a4be-c3cf-44a5-9052-a70314452305&displaylang=en To logon to the machine, use the following credentials: Username: administrator, password: Pass@word1 (Administrator account) If it is an ISO file, it should be a clean install, so the Password of the Administrator account is set by yourself when installing the system.Shaon Shan| TechNet Subscriber Support in forum| If you have any feedback on our support, please contact tngfb@microsoft.com