Is it possible to change the background color of the render window? If so How do I do it? I want to change it from the brownish color it is to white.

If you are just looking for options to get some better visibility here are a couple of suggestions:

When you have the render window active, press the A key to toggle lights on/off. Makes a big difference in visibility. I'm not aware of any other setting for changing default colours; however, with the lights on it turns my backgrounds from dark gray to light gray. I'm guessing your mileage will vary depending on your video card, just speculation on my part though.

Also, there was a tool I was told about called Explorer Suite that can be used to enable large memory addressing for GECK. I forget the exact procedure it was so long ago, but enabling large memory addressing definitely helped in making the render window look a lot better. especially when editing exterior cells. If you're interested you might search around on these and also Nexus forums for the details.

Thank you I appreciate the info