Toshiba is recalling hundreds of thousands of PCs after it discovered faulty memory modules could cause the computer to lock up and possibly corrupt data. The computers affected have been on sale since April 2002.

The recall covers 27 models of laptop. Toshiba has sold about 650,000 of them that contain the type of memory module in question, but only those from a certain supplier or suppliers are thought to be faulty and will be swapped, said a Toshiba spokeswoman. The total number of machines with the faulty module is unknown, she claimed.

The fault can cause the PC to wake up from sleep mode and cause a blue-screen of death, lockup of the PC or memory data corruption. Toshiba found the fault following an investigation earlier this year sparked by an almost identical problem discovered by HP.

HP launched its own recall and exchange program in late June. It warned that memory modules may fail when used with power-management techniques in Intel's mobile chipsets and processors. The flaw was found in modules from Samsung, Infineon and Winbond, HP said at the time. The company also said it found a different flaw in modules from Micron.

Toshiba refused to say whether its problems were the same as those identified and made public by HP over four months ago.

Machines covered by the program, which Toshiba has argued is not a recall, are: Tecra models S1, 9100, M1 and M2; Satellite models 2400, 2405, 1110, 1115, Pro M10, Pro M15, M30, Pro M30 and M35; Portege models R100 and M200/M205; Dynabook models T5, E6, V7, Satellite M10, SS S7, SS 2100, E7, V8, V9, VX1 and SS M200.

More details and a software tool to determine if a machine contains the faulty modules, are available on Toshiba's website. It will replace all affected modules until 30 April 2005.