Just yesterday when i turned on my powerbook, it ejected a DVD that had been in it for about a month. Naturally, I thought nothing of it and just tried re-inserting it. I heard the drive working, then after about 5 seconds make a noise and eject it again. This time I looked at the bottom of the DVD and saw two small brownish marks (burns??). The DVD smells somewhat burnt as well. Now, with every CD or DVD i insert, the same thing happens - its fine for 5 seconds and then spits it back out before any icon appears on the desktop or anything. I bought this computer used off of eBay, and it no longer has warranty or applecare. Does anyone have any idea about my situation at all (what exactly happened, how much it will cost to repair, etc.)?? Any advice or help or words of reassurance would be greately appreciated... I am scared.