The SOPC_BUILDER_CLASSIC variable does not work in Quartus® II version 7.1.
If you want the classic SOPC Builder GUI to open up from Quartus II version 7.1, you need to set the following environment variable:
SOPC_BUILDER_PREVIEW = 0
and then restart Quartus II.
To add this environment variable in Windows do the following steps :
Open the windows Control Panel (Start -> Settings -> Control Panel ).
Double click on the System icon to open the System Properties window.
In the Systems Properteis window, click on the Advance tab.
In the Advance tab click on the Environment Variables button to open the Environment Variables window.
In the Environment Variables window, click on the New button under the System variables section to open the New System Variable window.
In the New System Variable window, enter "SOPC_BUILDER_PREVIEW" for a Variable name and "0" for the Variable value.
Click the OK button to close the New System Variable window.
Click the OK button to close the Environment Variables window.
Click the OK button to close the Systems Properties window.