After what observers called a disastrous marketing campaign following its 2005 merger with Nextel, executives are trying to reinvent the Reston, Va., company's image with the new tagline -- "Sprint ahead" -- that omits Nextel, The Washington Post reported Tuesday.

Sprint also eased Nextel from sponsorship of the main NASCAR racing series. Starting next year, the Nextel Cup becomes the NASCAR Sprint Cup.

Television commercials, online ads, billboards and movie theater ads will debut Sunday. Besides trying to improve its network's reputation, Sprint is trying to hold off competition from AT&T and Verizon Wireless -- which benefited from Sprint's loss of customers, in part because of Nextel's network problems.

"This is the most important initiative the company's undertaken since the merger," said Michael Nelson, an analyst with the Stanford Group. "This is going to be a defining moment in whether they can turn around their business."

The new campaign focuses on Sprint's data network instead of industry shortcomings.

"We're trying to leave that behind and start a new conversation about Sprint," said Michelle Emerson, Sprint's vice president of brand marketing and integration.