Similar issue happened to me, just that it stop reading any kind of disc. Happened right after I updated fw. Got the replacement 8 days later, which was not my original system. It works fine, was just a little more scratched up than my original one.
Speaking of which, the best thing I have found to polish/remove minor scratches is a really really soft cloth and Mequires tech wax car polish and speed detailer. Apply the polish front to back, let dry and remove, then do the same thing again but left to right. Go easy on the playstation logo, unless you want to rub that off.
Then spray on a little speed detailer and buff lightly and quickly until dry and shiny. Don't rub hard, use just enough pressure to apply and remove.
I was going to ask Sony to send another system until I used the car polish.