Can you remove the battery and just use the power supply ? If still problematic, can you try with a different power supply and see if the problem persists
I have a dell Inspiron 7500 (win98SE,P2,128 mb ram bios ver. A04)that goes to sleep and must be rebooted and go thru scan disc every time. I have checked the bios settings and the power settings in windows off the screen saver tabs.

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