I have a scotts model # 42589x8. Iwouldlike to know who made it. What year it is. What the part # is for the deck and where I may possibly find one

Hi,
The info I found says it is a 1999 model. It was made in the Jackson, TN Murray plant that is the Noma division that they bought. Parts, especially major assemblies can be a bit difficult since Briggs & Stratton took them over a few years ago to pay their debt for engines. Both factories were closed and AYP now makes everything with the Murray name.
That said the deck assembly is a #710774-821 and a parts breakdown is at:
http://www.oscar-wilson.com/MANUALS/MURRAY/42589X8.PDF
Peace,
Clarke