Compaq Presario 7000 Lockup

A friend has a Compaq Presario 7000 running Win ME. < 1 yr old. It locks up after being dormant for a while (unknown time). Power off switch does not work. Must pull the power cable. Another user has the same problem, but can bypass problem by pressing "sleep" key on keyboard. Is there a fix through hdw, eg, BIOS upgrade? Can BIOS be flashed on this PC? Can tuning in Win, eg, power mgmt, help? Any other ideas?