I was testing stuff with render, render layers,scenes, world and cycle rendering. Suddenly my colornodes lost its shading. I went through I couldnt get it back.
Most likely you have accidentally put the HSV node to a value that blows out the resulting pixel values. See this screenshot here to understand which value I mean:
In your case, you have set this to 2.0. This will likely send so much light energy down the line that the resulting pixels will overshoot the 1.0 range, thus being clipped to white. I've done this in the screenshot below:
Lower that input value of the HSV node to something reasonable (between 0.0 and 1.0) and see if this resolves the issue.
thank you for stating your question clearly. At this stage you lost all information. Blender Render was created to NOT work with Nodes like in Cycles.
The moment you tried a different render method, the previous (Blender render) deletes all data stored at SCENE level, though at DATA-per-object level remains. (This is why you see the nodes, but they are all white). This is another reason why Blender internal and other functions in Blender cannot co-exist now that Cycles is better at doing light calculation.
Thank you for your consideration to vote me as the answer by clicking to the left :the icon with a check mark and upvote this answer.