after many problems with my computer a dell technician advised me to reinstall windows.  so i did, and when it came on for the first time i heard this awful beeping noise that wouldnt stop.  called techs again and had to check the backof the tower to see what letters were lit.  well one time ab another time I turned it on it was bd, ad, it just kept changing whenever I turned it on.  so i got frustrated. no one could help so i shut it off for a few days and now when i turn it on everything boots ok but i have no cd or dvd drive.  there is power to both of them but they arent listed under my computer.  i do not have internet access on it either because i need to put the cd in!  please help. very frustrated!!!!