Hi,

The digitizer (touchscreen) in the tablet either has a loose connection or is faulty.

Here is a link to the ifixit guide(s) to repair the tablet.

They are useful in that they'll help you to open the tablet to check the digitizer connection and also to gain access to the digitizer itself if you have to replace it.

Here is a link to just one supplier of a digitizer. It is not a recommendation to use them, it is shown to give an idea of the cost of the part. There are other suppliers that may suit you better. Just search for NuVision TM1088 digitizer part for results.

Hopefully this is of some help