If it's starting location is (1367, 100), and you subtract 5 from it each time, then it will never reach (1245, y) at all: the x coordinate will always end in a 2 or a 7, never a 5.
What I'd suggest is :
if (picbox2.Left <= 1245)
{
...
}
That way, it will start moving when it gets there, and continue moving from that point.