Hello,
I believe you have windows off the screen. That often happens if you use external monitors. first, try disconnecting external monitors if they are on, or reconnecting them if you recently disconnected them, restart sketchup and check if it’s still happening. otherwise :
Step 1 : press ALT+SPACEBAR
Step 2 : Now press M , which will basically choose the Move option
Step 3 : Now use the arrow keys on your keyboard to move the window to the new position that you desire.
follow these steps once you clicked on preferences, 3d text… or any other function that usually pops a windows out and makes you feel that sketchup is not responding anymore