If Randomize is not used, then the Rnd function (with no arguments) uses the same number as a seed the first time it is called, and thereafter uses the last generated number as a seed value.
To repeat sequences of random numbers, call Rnd with a negative argument immediately before using Randomize with a numeric argument. Using Randomize with the same value for number does not repeat the previous sequence.
Dim nValue, Response
Randomize 'Initialize random-number generator
Do Until Response = vbNo
Response = MsgBox("Roll again?", vbYesNo)