I bought a canon digital elph camera but cant take any pictures late at night any suggestions??

Night photography is always hard for a point and shoot. Because the elph doesn't have manual mode, you won't be able to adjust the shutter speed and aperture, which is required for night shots. But then again, the elph probably has a plethora of scene modes of which a night portrait and a night scene is probably included. Go through the scene modes and check those out.

Also, be aware. Night shots take a longer amount of time and thus are much more sensitive to camera shake. Definitely use a tripod.

The flash has probably been turned off. Check the users guide and set it to Auto Flash mode, and you should be OK.