Problem with preview

Hi everyone, I have a problem that I hope someone can help me, I have installed Dynamo but when I open a new file, the option of preliminary vita appears disabled and I can not see the geometry generated by the nodes and modify them already I have Intandado activate it using Ctrl + B but it does not work the same happens to me when the dynamo from revit someone knows what is the possible problem … in advance thanks

@Juvencio_Perez

Hi thanks for comment but that potions appear to me disabled that should be a problem with the video card or something like that