How To Make Motherboard Tray I Fixed This Xbox 360, Using The X Clamp Fix, But What Do These Signs Mean?

I fixed this xbox 360, using the x clamp fix, but what do these signs mean? - how to make motherboard tray

Okay. I bought this broken Xbox 360 broken with the seal of Microsoft Online ebay.com to about $ 60. I bought a metal and nylon washers, a series of small screws are the same size and shape as needed screws, a small silver mercury 5, a kit for opening Xbox 360, and a number of bits in the stars, Size T3 T10.

When I got my 360, I realized how easy it is blocked DVD drive when I open it. The case was deformed, evidence that someone is there before.

Having disarmed the case to the motherboard, I noticed something. Someone has already tried to solve the x-clamp.
(without consideration on which to install a new X-clip, but if you put the X-clamps and metal and nylon screws and washers)
I noticed that the magazine was a little different than mine, tAvailable in metal washers nylon washers. They also used screws surprisingly low.

the problem may have been? the fact that the radiator is not enough contact with the chips, because the screws are not tight enough?

I pulled loose the screws, and replaced it with my screws were the same size and thread. I also have Mercury Silver 5 on CPU and GPU, even with a credit card. I warmed with the fans, and he is removed to restore, then I have the case together. (DVD-tray was still attached) I tested it for an hour, worked very well. (one hour long enough?)

Did the previous owner get the rrod again because of loose screws?
I have nothing to fear, because the case was taken apart before, and almost the same situation was used?
I use the right ingredients? How can I solve the DVD tray?

Before you invest $ 60 in Halo 3, knows that if I made a stupid mistake. Thank you!