In White House Pitches, Rosy View of Health Care Site Excitement Before Health Site Went Live: Before HealthCare.gov made its debut, President Obama and his advisers predicted how user-friendly and beneficial it would be. WASHINGTON - Just days before HealthCare.gov went live with disastrous results, top White House officials were excitedly briefing lawmakers, reporters, Capitol Hill staff members and Washington pundits on their expectations for the government's new health care Web site. Led by David Simas, a senior communications adviser in the West Wing, and sometimes joined by Denis McDonough, the White House chief of staff, and others, the fast-paced PowerPoint briefings showed images of a shiny new Web site that was elegantly designed, simple to use and ready for what officials hoped would eventually be a flood of customers on Oct. 1. One lawmaker recalled comparisons to Travelocity, the travel booking site. In fact, the rosy presentations set President Obama up for even more criticism when the portal was swamped by millions of people who quickly found out they could not log on. The technical problems that emerged have raised questions - still not entirely answered - about how much the president's aides knew, or should have known, about the site's troubles. "We knew this was a complex undertaking but did not see the huge volume of demand coming," Mr. McDonough said in an interview this week. And that volume has exacerbated, as the president said the other day, the underlying problems. The fact is we'll get to the bottom of it and get it fixed. The issue of when administration officials recognized the Web site's potential for major problems has emerged as one of the key political talking points on Capitol Hill. During a hearing Thursday of the House Committee on Energy and Commerce, angry lawmakers grilled executives from the private companies hired to design and build the site about whether they had warned government officials. The executives testified that "end to end" testing of the Web site did not take place until two weeks before the site made its debut - about the same time that the briefings by Mr. Simas and Mr. McDonough were taking place. And they said problems with the software that powers the Web site were communicated to senior officials in the president's administration. Cheryl R. Campbell, a senior vice president of CGI Federal, a unit of the CGI Group, the main contractor on the federal exchange, said that all of her company's work had been done "under the direction and supervision" of the federal Centers for Medicare and Medicaid Services, known as C.M.S. Andrew M. Slavitt, the UnitedHealth executive responsible for Quality Software Services, told lawmakers that "we made everyone aware of the risks that we saw." He added later, "We informed C.M.S. that more testing was necessary." Some specialists involved in the repair effort have estimated it will be six to eight weeks before the online system operates tolerably, and longer before all the kinks are worked out. According to some accounts, the project's managers at the Department of Health and Human Services assured the White House that any remaining problems could be worked out once the Web site went live, but other senior department officials predicted serious trouble and advised delaying the rollout. But on a conference call with reporters on Thursday, Centers for Medicare and Medicaid Services officials twice declined to answer questions about whether Kathleen Sebelius, Mr. Obama's health secretary, knew about the problems. Asked if Marilyn Tavenner, the agency's director, or anyone else had alerted Ms. Sebelius, an official cut off a reporter. "Next question," he said. Mr. McDonough said in the interview that officials "anticipated bumps and glitches and problems." But he and other White House officials declined to say specifically what information officials at the Centers for Medicare and Medicaid Services and the Health and Human Services Department communicated to their counterparts at the White House before the Web site was opened to the public. Jay Carney, the White House press secretary, said this week that "we did not know until the problems manifested themselves after the launch that they would be as significant as they have turned out to be." The briefings in late September, including one for editors and reporters at The New York Times on Sept. 26, were designed to counter assertions by Republicans that the federal health marketplace would not work and was not ready. Mr. Simas, who worked as one of Mr. Obama's polling data analysts during the 2012 campaign, served as the top pitchman, eagerly whipping through graphs and charts. The briefings focused largely on the Web site's appearance and ease of use, rather than the software powering the site. Robert Pear contributed reporting from Washington, and Sharon LaFraniere from New York.