This is a somewhat "advanced" tutorial on post scan mesh/point cloud manipulation, and assumes you have a properly working scanner.

I think you probably need to go back to the basics and get the scanner working correctly first.  I see you already started a thread on the camera, you should also ask your questions about why you're having problems with the high res scans and the turntable turning off mid-scan.

So now we have all the layers properly aligned.  At this point you might want to check the composite cloud to make sure everything is aligned properly, also do a bit more clean up.  Since the composite is still made from multiple layers, we now want to combine all the layers.  This is done by using the "Flatten Visible Layers".

When flattening the layers, you can choose to delete or keep the original layers.  For now, uncheck the "delete layers", and click "Apply".  A new layer will be created out of all the aligned layers.  The new layer will not have any color information.

Check the new payer for any random or stray pixels, and do any clean up that might be needed.

Next up, we'll Compute the Normals for our point cloud, then run the Poisson Surface Reconstruction to generate our new mesh.

And here is the final result.  I hope this helps. 

Make the second layer visible, then click the "point Based Gluing" button.

A split window opens up showing both the first and the second point cloud.  You will notice that both side will zoom in and out in sync when you use the scroll wheel.  First try to align the 2 views as close as possible, the look for areas on the point cloud that have common reference areas, usually intersections and corners are good reference point. 

Pick a point, and double click on it.  A small blue dot appears with a number next to it.  pick the same point on the other view.  repeat the process in various areas of the model.  A minimum of 4 reference point is needed, but the more you add, the more accurate the alignment will be.

When done selecting the points, click the "Allow Scaling" checkbox.  this lets MeshLab "stretch" one mesh to fit the selected alignment points.  In a perfect world, this wouldn't be necessary, but due to a variety of variables (calibration, perspective, location, depth of view, etc), the meshes are not identical, so a little stretching will be necessary to properly align them.

Repeat the process for the remaining layers.  When all the layers are aligned, click the "Process" button.  When finished look at the last line of the process will show and error number, like this: "error bound 0.0010".  The lower the number, the better the alignment.

Close the  Alignment Tool box, and save the project.  this only saves the data regarding the alignment of the layers, not the individual layers.

Next...

One solution to solve this problem, is to change the angle from which you scan the object, and perform multiple scans.  Each scan will see a part of the model which the other scan didn't see.  Once you have most or all the areas covered, you can align the individual scans and get a fairly complete scan.

This tutorial deals with the alignment of these scans, but here is a brief rundown on how I achieved the multiple scans:

The first scan is done by placing the model in the center of the turntable, like we usually do.  For the second scan, the model is brought forward near the front edge of the turntable, This will give a different angle for the front and back, but not much on the sides. Next I tiled the model back at ~45°.  I propped it up using a thin (1mm) wire, simple but effective.  Last I did the same thing but this time I titled it forward.

Each scan was done at 5MP, and 1600 steps (about 50 minutes per scan).  Once you have all the scans, we need to assemble them and align them into a single mesh. 

NOTE:  Cleaning a model is a very important part of this process.  Using a scan with lots of noise will result in a very poorly aligned model, and a poor quality resulting mesh.  So please clean up your scan before attempting to align them.  Check my other posts on how to clean up a model in MeshLab

First we start by opening MeshLab.  Next, click File, Import Mesh, then navigate to where the scanned files are and select them.  You can multiple select by holding the SHIFt key (sequential files), or the CTRL key (non-sequential).

Next, all the meshes load on the main screen overlapping each other.  Notice the angles at which they open.  These are the angles at which they were scanned.  Additionally, the layer screen should automatically open as well.  If it doesn't, just click the Layer view button on the menu bar.

By default MeshLab enables the "Flat" view, but we want to see the actual point cloud, so click "Point" view button, then Click the Align button.  This opens up the Align Tool window. 

The first thing we need to do is change a few things.  Check the "Use Point Rendering", and uncheck Use False Colors.  The false colors option is only useful for meshes without color information.  Next make only the first layer visible, then click the "Glue Here Mesh" (Hmmm... must be Yoda speak for glue mesh here ).  This makes the first layer the reference layer to which the other layers will be aligned.