dvd not working

iMac early 2009, dvd problems. dvd doesn't show up in system preferences either. Occasionally I will get an initialization error. Mostly iDVD player will not open when I insert a disk, also it won't play a commercial dvd. I recently installed a logitech wireless keyboard and a wireless apple mouse. I can open the dvd player from the applications sometimes. but it can b hit or miss. I'm not super technical but have some knowledge.