Ahh, the joys of having non-Sony made equipment (GC)...
Either way, it's beginning to be noticed that the PS2 has problems with positions.
You see, gears, UV readers, receptors, ect. wear in the position that gravity pushes them. So... if you change your PS2's position from vertical to horizontal, or vice versa, you'll be literally wearing the the components out on the other side as well. I talked with a friend of mine at EB, and he stated that in the last 6 months, he's been having PS2 owns complaining about how their GTA3 or MGS2 no longer works because of these "rings" circling the middle and out layers of the disks. Also, using both horizontal and vertical positions on and off potentionally cuts your PS2 life
by a quarter or more.
Way to correct this?
Don't change the PS2's position, and make sure it's on a stable surface.