The laptop powers off suddenly even with adapter plugged in. I keep it plugged in 100% of the time. I have never replaced the battery because it says it is 100% charged, however I rarely use it with battery only as the life is less than one hour. No consistent pattern with the power-off, purely random. Is this most likely a power supply getting ready to die or could it be a bad battery interfering with the laptop operation or perhaps overheating? The unit is quite warm, but not unreasonably hot when this happens. Last, I do not routinely shut off my laptop. It stays running 24/7 and just goes to sleep when I'm not using it. The fan seems to be working fine.