Well, The freezing is usually a cpu overheating due to dust in heat sink or to many things turned on when the system boots up. You would have to go into config file and turn off some stuff in the startup tab or as stated in previous postby sundance, a ram issue. The screen staying black is usually a back light problem but if you are twisting it a little and it coming on, then you have a ground fault problem. A pin bent or something when he removed the cd rom drive. Especailly if the drive will not work at all. Unpluging and plug a drive up on a laptop will usually not do much until you do a reboot for the drive to come back to bios. I would almost think that a pin has been knocked out of place. Look at the rom drive pins and take a flash lite to see if you can see the pins on the motherboard in the rom slot.