Computer maker Dell Inc will reduce more than four years' worth of earnings by up to $US150 million ($A183.52 million) after an internal probe found the company misled its auditors and manipulated results to meet performance goals.

The struggling company said that its net income for the restatement period will be reduced by between $US50 million and $US150 million ($A61.17 million and $A183.52 million), or two cents to seven cents a 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 per cent and 13 per cent.