Office 2007 License

We have several users on office 2007 and we created a backup disk from microsoft of the office 2007 suite.
We are wanting to buy office 2007 for a computer that we already have (currently on office 2003) but can only find it in the MLK version – is it ok to run the office 2007 backup disc on the old PC then activate it using the MLK code?
Thanks