Alright, I took the PS2 apart, resoldered the CD/DVD wires on the bottom-side of the motherboard so that they were more secure, cleaned the wires up a bit, took off the piece of two-sided tape under the DMS3 (probably what was keeping it from booting when closed), put electrical tape over every solder point, and put it all back together.
Well, the PS2 doesn't freeze anymore, and it boots just fine.
However, it still won't boot my PS2 CD-R backups!
It boots everything else just fine!
Any suggestions on what it might be? Remember, I've already re-soldered the CD/DVD wires (R through W).
By the way, on the BIOS (D through N), I've soldered E through I to the pads in the install diagram, except for wire D. I soldered this directly to the pin. Could this be a problem?
Here's a diagram if you don't know what I'm talking about.
So now what do I do?