Tool bar buttons greyed out, trouble sketching

[Anonymous]

Using Inventor trial version.  Certain buttons on my toolbar (most importantly sketching functions and undo/redo) are grey and not clickable.  Even though "Start 2D Sketch" button works fine, but once I click a plane it won't go into sketch.

It is like this in all parts, all different files, even new parts. 

I reinstalled the program, restarted computer, etc. 

It was working fine earlier today. 

I attached screenshot below 

[SharkDesign]

Mine looks exactly like yours, but once I click start sketch and pick where I want to sketch all the grey icons become usable. 

[johnsonshiue]

Hi! Do you happen to have another file open in a different monitor? It looks like the other document is active at the moment.

Many thanks!