Shares in Dell fell 10.3% on Wednesday after the PC-maker slashed its sales growth forecast late on Tuesday, blaming a ''more uncertain demand environment''.
Hewlett Packard also fell some 4.1% by mid-afternoon in New York.
Dell said it now expected revenues to rise only 1%-5%, down from 5%-9% before.
This was despite the company posting net income for the second quarter of $US890 million, with net income rising by 60%.
The BBC reports the increased profits were due in part to expansion by Dell into higher margin businesses, like servers, data storage and computer services.
Revenue was 1% higher, lifted by stronger spending by companies and the federal government.
However, governments, companies and consumers are all expected to moderate their spending during the rest of the year.
