If you set a raster snap setting and you cannot see the snap window, then make sure your drawing VPOINT is set to 0,0,1.
If you still cannot see the snap window, then adjust the snap window size or try zooming into the image. The size of the snap window changes when you change the zoom level.
When you use raster snapping with AutoCAD OSNAPs, the OSNAPs take priority. You can press F3 to turn off any running OSNAPs if they are conflicting with the raster snaps.
For more information, see Raster Snapping.