NEW YORK (CNN/Money) - The stocks of enterprise software and hardware suppliers led the U.S. technology sector lower Tuesday amid further signs that large corporations still have not loosened their IT purse strings despite apparent improvements in the economy.

A series of earnings warnings put particular pressure on the software segment. Hardware makers were dogged by a less optimistic outlook from Goldman Sachs, which lowered its quarterly earnings estimates for several big-name outfits.

The Nasdaq composite index ended the session 57.66 points lower at 1,804.96, a 3.1 percent decline on the day. The tech-laden index had managed to hold onto a modest gain on Monday as the broader markets moved deep into the red.

Shares of enterprise software specialist PeopleSoft (PSFT: down $12.21 to $25.16, Research, Estimates) topped the Nasdaq's most active list Tuesday, ending the session more than 30 percent lower.

Before the U.S. markets opened Tuesday, PeopleSoft warned that it's first-quarter earnings will fall short of previous forecasts, blaming a cautious technology spending environment for weak product sales.

Shares of BroadVision (BVSN: down $0.25 to $1.47, Research, Estimates), which also makes enterprise software, fell sharply on Nasdaq as well, shedding more than 16 percent of their value.

After Monday's market close, BroadVision warned that its first-quarter revenue will be lower than recently expected, blaming "continued uncertainties surrounding the current information technology spending environment."

The company also restated its financial results for the third quarter, fourth quarter and fiscal year ended December 31, 2001. It said the changes were related a software license agreement, originally recorded in its entirety in the third quarter of 2001, that instead should be recognized ratably over its four-year term.

Both PeopleSoft and BroadVision were on a list of enterprise software and hardware companies for which Goldman Sachs on Tuesday lowered its earnings estimates.

Comments from analysts at the firm supported the general thesis that corporate IT spending, which has fallen sharply over the past year amid an economic slowdown, is not improving at a rate commensurate with economic improvements.

Goldman also lowered its earnings estimates for Microsoft (MSFT: down $3.08 to $57.30, Research, Estimates), the world's largest computer software supplier, as well as several big-name enterprise hardware makers.

Among them was IBM (IBM: down $1.91 to $100.95, Research, Estimates), the world's largest supplier of computer hardware and information technology services. The firm said that while there appears to have been a general pickup in IBM's hardware business at the end of the March quarter, the uptick probably was not sufficient for IBM to achieve its original revenue forecasts.

Sun Microsystems (SUNW: down $0.58 to $8.94, Research, Estimates), the top supplier of UNIX servers, also was on Goldman's list, as was EMC, the top maker of data-storage systems.

As a group, software stocks were Tuesday's worst performers. The Goldman Sachs computer software index ended the session 10.72 points lower at 155.51, a 6.5 percent decline on the day.

Hardware stocks weren't far behind. Goldman's computer hardware index fell 7.79 points, or 3.2 percent, to 239.22.

The stocks of telecommunications and data-networking equipment makers, which led the tech sector higher Tuesday, for the most part gave back those gains.

Shares of Sycamore Networks (SYCM: Research, Estimates), which specializes in optical networking equipment, fell 5.6 percent. Deutsche Banc Alex. Brown on Tuesday downgraded its rating on Sycamore's shares to "buy" from "market perform," citing a slow pace of customer acquisitions and a high cash-burn rate among the reasons for its less optimistic outlook.

Other networking stocks ending lower Tuesday included: Cisco Systems (CSCO: down $1.10 to $16.42, Research, Estimates); Juniper Networks (JNPR: down $0.84 to $12.39, Research, Estimates); Nortel Networks (NT: down $0.22 to $4.41, Research, Estimates); and Ciena (CIEN: down $0.44 to $8.93, Research, Estimates).

The American Stock Exchange's networking index ended the session 7.91 points lower at 241.51, a 3.2 percent decline on the day.