Disk tray problems

Hello! I had a problem with openning the disc tray but then going through the internet I read an article here that helped me to open it. Unfortunatly now that I am able to open the disk tray, once I insert the disk that I want to watch for example, it won't read the disk and I don't know what to do since I don't really know how to use laptops that well. My laptop is a Dell Inspiron 1525. I would really appreciate it if you would help me and give any kind of advice.