Dell Inc. (DELL), one of the world's largest PC makers, said Thursday that an internal audit committee has found a number of accounting errors and evidence of misconduct in its monthslong review of previous earnings statements.

Dell also said it would miss an April 18 deadline to file its annual 10K financial report to the Securities and Exchange Commission until the internal review is completed.

Dell shares fell in electronic trading after the market closed, when the news was released.

In a short news release, the Round Rock, Texas, company said the internal audit had "identified a number of accounting errors, evidence of misconduct, and deficiencies in the financial control environment."

Further details were not provided, and Dell spokesman Dwayne Cox said the company was unable to comment further.

The company added in the statement that it was working with management and the company's independent auditors to determine whether the errors would require the restatement of previous earnings reports.

"As we move toward the conclusion of our investigation, we are committing the time and resources required to ensure a thorough and comprehensive review and resolution of all identified issues and the implementation of appropriate remedial measures," Thomas W. Luce III, chair of Dell's Audit Committee, said in the statement.

The company did not say how much longer the internal investigation would last.

Dell's earnings statements from the second, third and fourth quarters remain preliminary and have yet to be filed with the SEC.

In August, company officials said Dell received a letter from the SEC in August 2005 asking broad questions about some revenue recognition. Company executives initially shrugged it off as an informal investigation and something that happens to hundreds of other companies.

But it has since grown into a formal look by federal investigators into Dell's finances. Dell also faces a slew of shareholder lawsuits, and the U.S. attorney for the Southern District of New York has subpoenaed documents related to Dell's financial reporting since 2002.

Shares rose 4 cents to close at $23.39 in trading Thursday on the Nasdaq Stock Market, then fell 1.6 percent in after-hours trading to $21.80.