Join Date: Mar 2009
Location: Manchester, England
Yep, GW did indeed say that there was no link between the two, despite the Old Ones appearing in both.
The Warhammer Fantasy Old Ones came in 'great, interstellar ships' to the Warhammer World, and decided to add it into their plans (whatever those may be). They themselves didn't manipulate the world; they created and gave powers to the Slaan, who manipulated the world's orbit to make it warmer, split continents and created great oceans (known as the 'great pond' to Lizardmen). The North and South Gates were created, and the North gate collapsed either before or after the Old Ones left, resulting in Chaos spilling forth.
In Warhammer 40,000 the Old Ones were a race of great power, but weren't considered god-like as they are in WHFB. They had great technology, but found themselves undone by the Necrontyr and their dark 'gods' (Deciever, Nightbringer etc) and so created psionic races (Eldar) to counter them. But then the Enslaver Plague occured, and bye-bye Old Ones. They died, whereas WHFB Old Ones simply left.
Hope this helps.