Computer maker Dell Inc. on Thursday said it would reduce more than four years’ worth of earnings by up to $150 million after an internal probe found the company misled its auditors and manipulated results to meet performance goals.

The struggling company said its net income for the restatement period will be reduced by between $50 million and $150 million, or 2 cents to 7 cents per share.

The largest reductions in quarterly profits were expected to be in the first quarter of fiscal 2003 and the second quarter of fiscal 2004, each lowered between 10 percent and 13 percent.

It will restate all of fiscal 2003 through 2006 and the first quarter of fiscal 2007, in total.

The investigation, which began in August 2006 and evaluated more than 5 million documents, “identified evidence that certain adjustments appear to have been motivated by the objective of attaining financial targets,” Dell said.