Result not visible when using Blender Render I have such object (based on this tutorial):


When I use Cycles Render I see correct result as expected: 


But when I switch to Blender Render I see gray screen:


Does anybody know what is going on here?
Blender Cycles expects Cycles Materials.
Blender Render expects Blender Materials.
They are not shareable across render engines.

If you replace your materials with Blender Materials then you can use Blender Render.  You can try a test by replacing one or two materials.  You might want to archive your file or create a different scene to keep the original intact.