Sorry, thats my fault, I was thinking in terms of the axis of the object and the co-ordinates of the mouse being opposite but obviously the mouse and object screen positions should be of the same co-ordinate mapping. I.e. 0,0 is top left, 640, 480 is bottom right etc. But still, try actually displaying the co-ordinates of the object and mouse to see if the ranges are correct, and also place the sx-100, sx+100, sy-100 and sy+100 in brackets to ensure there's no confusion of B.O.M.D.A.S
"Man who looses key to woman's appartment...... He get no nookie" - A wise chinese man.