Is it a grinding noise or just a fast slow spin noise? Grinding could be the magnetic disc that holds the cd on the spindle coming loose, the spin down sound could be the spindle needing some lube, or the laser could be trying too hard to read and need an adjustmenth:

And if you ever get the 3 red lights your gpu probably came unsoldered from the MB due to some strap they used for the heatsink applying pressure warping the mb. Under the hot/cold conditions the solder will soften and harden eventually letting the gpu lose some contact. I found a fix for this as well.