Setting up a potential bidding war over Dell (NASDAQ:DELL), both billionaire Carl Icahn and private-equity giant Blackstone Group (NYSE:BX) reportedly expressed interest in the PC maker ahead of a Friday deadline. The apparent interest from the deep pockets of Blackstone and Icahn raises the chances of a bid emerging that would top the original $24.4 billion offer from cofounder Michael Dell and Silver Lake Partners. According to The Wall Street Journal, Icahn and Blackstone notified Dell's special committee before the midnight Friday close of the go-shop window that they are working on firm bids. The notification gives the potential bidders four more days to put together firm offers, the paper said. A source told the Journal and other publications that Blackstone has already submitted a preliminary bid Blackstone has reportedly aggressively recruited former Hewlett-Packard (NYSE:HPQ) CEO Mark Hurd to become CEO of Dell if it pursues a bid. Icahn had been pushing the Dell board to enact a dividend recapitalization plan if shareholders reject the management LBO.