Round Rock, Texas--In a clear sign that it views marketing as a way to reverse the plunge in PC sales, Dell has tapped Michael George as chief marketing officer, a newly created position. George, 39, was partner-retail practice at McKinsey & Co. before joining Dell earlier this year as an executive assistant to Chairman-CEO Michael Dell. McKinsey vets have a reputation for quickly rising to the inner sanctums of the Fortune 500 companies they used to advise. The New York-based blueblood firm's alums include IBM Corp. Chairman-CEO Lou Gerstner and former CBS Television Network Chairman-CEO Michael Jordan. Dell is going through its grimmest period in recent memory, as sales in its core PC product line are slumping. Dell recently took a $700 million charge to account for layoffs and other items.