Clive2002
It would be nice if you could actually send some test data, i.e. you could paste the areas into word as tables instead of pictures, better still zip the XLS and post that.
de-normalise is not a real word but I think we get your drift, in fact if the data were normalised and residing in a database it would in all likelyhood look like your required output. (maybe reversed depending on any other links). Because you should never store more than one thing in one field.
Having looked at your data it seems to be that maybe a redefinition of the problem may be in order (to ensure I've got the right end of the stick).
You have a 3 column input ; Product Key, Avaliable Attachments and Attachement List
Attachment List : contains a list of Attachments for a Given Product Key, separated by commas
Available Attachments : may be ignored as what are you going to do if this says 20 and there are only 18 items or visa versa ?
You don't say if we can delete the original list or where you want the new list (which will have the Product Key repeated until no more attachments for that Product exist) do you want this as a new sheet or offset from the original list (to the right or below) ???