Scanning probe microscopy (SPM) with a conducting tip has been used to electrically probe silicon nanocrystals (NCs) on an insulating substrate. NC samples were produced by aerosol techniques followed by a sharpening oxidation. The size of NCs is in the range of 10-50nm and deposited on a silicon substrate with a density of around 1011/cm2. Using a conducting tip, the charge was injected directly into the NCs, and the bias dependent images due to the trapped charges in the NCs were monitored. Charging effects affected by the size of NCs and injection direction were also estimated from the apparent height differences of the NCs with respect to the applied bias.