LCD won't display and getting a busy message from

You may have a problem internally, and the camera may need repairs.
But, let us try to see if we can help.
On the external of the camera there should be a button for turning on the display and setting in different modes. Some cameras of this kind will not show through the LCD, but uses the viewer for picture taking, and the lcd for viewing playback views.

Go to the menus and set all to default. This camera may have a setting to set all to default. After, test the camera.
If after testing to what I have stated, and still the camera is doing the same, then I recommend to call Canon repair.
Call Canon from the website toll free number for the repair department. Canon's support is great, tell them your camera model and serial.
They may solve your problem by phone, or you may send it to them for repair. Canon has a great trade-up or trade-in program. This may be an option which may interest you if you cannot fix the camera.