My 2001 P38a HEVAC display screen is having an off day. It shows a black screen when the car is started and sometimes comes back on after the car is driven a few miles. At other times it responds to tapping the screen. The screen seems to have a small amount of movement and pressing the edge one way or another results in the display operating normally. I have read posts on this forum and on the rangerovers.net forum. which explain how the unit can be removed from the car and very helpfull on some repair jobs. However the screen problem that I am experiencing is not covered. Can anyone suggest what might be wrong. I intend removing the unit but it would be helpfull if I had some suggestions to commence the repairs.