no autoplay or explore on cd/dvd drive

No matter what type of disc I insert into my cd/dvd drive it will not
autoplay, and I cannot even explore the drive to find what is on the disc.
The only way it is possible to use the drive is to: select Computer - right
click on the drive icon - select search - and type in a file extension (such
as .exe) or type in setup etc. When I guess the correct search criteria a
list of files contained on the disc are displayed, enabling me to double
click the desired file. This will then start the drive and I am able to use
the program or listen to the music etc.
I am running Vista Home Premium on a new computer. The drive worked
perfectly well for the first two weeks but suddenly developed this fault. I
have fitted a new CD/DVD drive, have selected "use autoplay for all devices",
and have set all default programs to "ask every time.
I am absolutely stumped, can someone please offer a suggestion to fix this
before I rip out what little hair I have left.
Thanks.