Hi p(3.14), I don't know if this will help or not. The "old" way of collision detection is as follows:

Code:
procedure TPlayerSprite.DoCollision(Sprite: TSprite; var Done: Boolean);
begin
  if Sprite is TMonoSprite then
    TMonoSprite(Sprite).Hit;
    Done := False;
end;
The "new" way, also used in unDelphiX 1.08 is:

Code:
procedure TfrmMain.CarCollision(Sender:TObject;var done:Boolean);
var
   theMan : TMan;
begin
     if (sender is TMan) then
        begin
             theMan:=TMan(sender);

             if (not theMan.hit) then
                begin
                     theMan.Image:=dximgs.Items[fBloodImageIndex];
                     theMan.Z:=-30;
                     theMan.hit:=true;

                     fScore:=fScore+100;
                end;
        end;
end;
Then in your _psStartingState:

Code:
Car:=TCar.create(dxspriteEngine1.engine,dximageList1,CarImageIndex,_startingGas);       Car.OnCollision:=self.carCollision;
Maybe it will help you :-) My game written in unDelphiX is also full screen but I don't have the alt tab crash...