NEC Corp. and Fujitsu Ltd. are voluntarily repairing and exchanging parts in certain models of their personal computers that may be defective, officials of the two computer makers said.

NEC has received 74 complaints that its Lavie NX and Versapro NX notebook PCs are heating up to temperatures near 90 degrees when their covers are closed and the machines are on. There have been no reports that any have caught fire.

The company has shipped about 2 million of the two computers since October 1999.

Fujitsu has reported some of its FMV desktop PCs are malfunctioning when used for extended periods in hot and humid conditions, in some cases being unable to start up.

Fujitsu produced about 27,000 units of the FMV series between September 2000 and January 2001.