RadioShack, once a wildly popular retail home for tech fanatics, has long since lost its luster and now the time has come to shutter some stores.The company on Tuesday announced that it will close up to 1,100 stores across the US. RadioShack didn't say how long it will take to close the 'underperforming' stores, butit seems to be set on moving as quickly as possible.That RadioShack is closing 1,100 stores has surprised some who had been under the impression the company wouldn't act so aggressively. Last month, the Wall Street Journal reported, citing people who claimed to have knowledge of its plans, that RadioShack would only close 500 stores.After the closures, RadioShack's US stores will number about 3,100 to 3,200. The company will also have 900 dealer franchise locations, bringing its total presence across the United States to 4,000 locations.RadioShack is in the midst of a rebranding intended to make its retail locations more friendly to today's consumers, rather than a hub for folks who need parts for their gadgetry. The company said that its remaining stores will have a new product assortment, and that in stores where it has already made the conversion, sales are up.Still, RadioShack had a difficult fourth quarter of 2013, reporting $935.nike shoes4 million in revenue, compared to $1.nike shoes2 billion in the prior year. The company's annual losses also widened, jumping from $139.4 million in 2012 to $400.nike shoes2 million in 2013.