cd/dvd drive problem with Autoplay

I am operating windows xp home edition on my desktop pc. Previously whenever I inserted a cd or dvd into the drive, it would bring up a box asking me what I wanted to do with the disc. This is now not happening any more. I have been into my computer and right clicked onthe drive and reset the auto play instructions, all to no avail. I have been told that I may have a specific file missing from the registry. This is beyond my knowledge base. Can someone please help me with this problem?
( I am not sure if it is related, but putting a usb flash card into the usb port used to also bring up a box asking for instructions as to what i wanted to do. This is not now not happeneing with this port either )

 

Thank You Pete

It fixed it!!!!