I'm not sure what you have done, it seems like you have tried both nurbs-modeling and polygon-modeling. But I feel that this will be helpful:
Consider using the circle primitive. It's but a circle but pick vertic-pairs and scale them so that they move closer or further away from each other. Alternatively pick the vertice-pair and use the move tool to move them up or down. The point is that you get to keep the symmetry this way.
About attatching curves:
If attatching curves doesn't seem to work (the way you want), then either reverse the curve direction for the appropriate curve. If you right-klick the curve(s) and view the vertices, you will notice that the curve has a small square and a small U shape around the first two vertices on a curve. The small square is the first vertice on the curve, the U is the indicator for which way the curve runs.
About pivot points:
Use the "insert" key on the keyboard to go into "alter pivot-point-position". Useful for accuratly duplicating/mirroring curves around/about a centerpoint (e.g like in the grid center).
About modeling techniques:
There is probably several way to make that board of yours,
Here's what I think:
A (nurbs) (Keep history button on for less work)
1) Tweak a nurbs-circle into a rounded square, pretty easy
2) Duplicate it about three-four times and keep a little space between them, with history button on you can loft these and move/tweak the curves while wathcing the lofted shape follow the curves along the tweaking.
3) Scale the outer-most curves a little innwards
4) Loft the curves with "square degree" or linear lofting.
5) For making the front-side-frame duplicate the outer-most curve and scale it innwards.
6) Loft the last two curves.
By now I think you get the idea.
1) Make a poly-cube-primitive, and duplicate it. Scale the smaller one down but make the depth deeper than the bigger one, because you will pick:
-the big cube and shift klick the small cube and select "Polygon --> Boolean --> Difference" for making an edgy frame.
2) Open Bevel Options under Edit Polygons
3) Set roundness to about 0.3 - 0.5 or something like that
4) Set the radius (important) to a low value. If your cube is 1 meter wide, try 0.1 in radius.
5) Pick the poly-frame and press the apply in the bevel options window, if your results wasn't satisfactory, press Z to undo it and try again.
6) The normals usually get all messed up with the bevel tool, so you have to get them to get along with each other.
EditPolygons --> Normals --> Set to face
And... for soft corners...
EditPolygons --> Normals --> Soften/Hard
7) Make another cube for the screen, you'll have to scale it down to fit it inside your rounded poly-frame.
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