How do I add collision to objects?

check if the sprite is going into something, if so, move the sprite back to where it was before it moved into it.

Like SPHITSP?

You can judge collision by distance between two objects. You can calculate it with the Pythagorean theorem as follows. DX=X2-X1:DY=Y2-Y1 D=SQR(DX*DX+DY*DY):'distance between two objects

Ok! Thanks!