dvd rom not working

please help me
my cd-dvd rom drive is not working
first i have samsung sd series dvd rom drive.
it is shown in device driver list with an exclamation mark.
the trouble shooter says windows can not find drivers needed due to error code 31.
i tried various downloads for driver .but the problem exists still.
after i connected creative infra 52x cd drive,instead of samsung.
i downloaded the setupcr.exe for it.but it says ctinfra.dll is not found.
creative cd drive also as samsung .
will u please help to do any solution .
thanks in advance.