I put my book on Amazon's Kindle in 2012 and am now attempting to put the same book on Lulu for POD, etc. I have already got an ISBN for the Lulu version. Is this okay to have the two running together? Thank you.
Yes - if you are publishing a print version on Lulu, there will be no conflict.
You cannot, however publish an eBook version on Lulu and distribute it to the Kindle store as that would be a duplicate publication.
Thank you - that's made it clear.