BO Upper part missing after update to 1.5.6.2

[cleaner]

Hi, 

 

Fresh and initial 1-click install of Presta using version 1.5 provided by my hosting company. After that 1-click update to latest 1.5.6.2. 

 

After update navigation bar is missing on BO. It will be visible if clicked to a black area (please see attached image).

 

Browsers cache is cleared and template cache "force compilation" is done. Despite of this everytime i login/ refresh BO. page,  menubar disappears and only clicking to black area brings it back.

 

Any idea what's causing this?

 

thanks again in advance,

 

-cleaner