Question for you pros

If I buy a domain at a domain auction that's quite old and already has some pagerank, then will the pagerank go down to 0 once I start putting up my own content?

If so, then can I try to put up similar content, in keywords and everything so that google thinks that I just renewed the registration and the website is still about the same stuff?

For a long time they'd lose their rank 100% of the time, now people tell me it's kind of a gamble.