How to see if the laser works?

You do not want to look at the laser it can do permanent damage to your eyes. The answer is rather obvious, though not the answer you are looking for. If you put a disk in and the disk spins and it reads disk(s) it is working. If it is spinning disks but not reading them then I would try cleaning the lens with isopropyl alcohol to do that you will need to disassemble the PS3 to get to it. There is a link to a guide below that will show you how to get to the laser. If cleaning it doesn't work the laser assembly needs replaced. You can find replacements here or on eBay. Instructions for replacing it are here. Please look at the tool requirements in the repair guide before you begin. You will also need to purchase the correct laser assembly, all pS3s do not use the same one. You will need to get the part number off the assembly.