hello . what is meaning this error , when I want to install sql server 2005 ?
None of the selected features can be installed or upgraded. Setup cannot proceed since no effective change is being made to the machine. To continue, click Back and then select features to install. To exit SQL Server Setup, click Cancel.
It thinks you are upgrading a systme already installed rather than a new instance. Check installed programs to see if there is a previous version; if you are doing a new instance make sure you specify it as you go through the wizard.
The message is pretty self-descriptive. The installation doesn't believe you're making any changes to the machine. Google/MSDN/Microsoft Help is a much better forum for this question than stackoverflow.