New York, March 28 (BridgeNews) - The Nasdaq plunged 6% and ended below the key 1900 level after profit warnings from Nortel Networks (NT) and Palm Inc. (PALM) sent technology stocks reeling. The broader market also declined after a three-day rally on concerns about the dismal outlook for corporate earnings. The Nasdaq closed down 118.34, or 6%, to 1853.92 and the Dow was down 162.19, or 1.63%, to 9785.35. The S&P 500 was down 28.92, or 2.45%, to 1153.25.