I am using XP Home with SP3 on Acer Laptop Travelmate 244LM

For 5 years my P.C. always started the day with 98+% full charge after a night powered down.

Two weeks ago it started the day at 0% and gradually built up 1% point at a time for a couple of hours.

Every night I instruct a normal SHUTDOWN, and after everything has completed, and the LED's go out and the fan stops and the display blanks out, then I shut off the mains power to the battery charger.

I suspect as possible culprits :-
1.  Something woke up the computer and it stayed awake until it exhausted the battery, or
2.  The shutdown software correctly turned off MOST of the hardware, but perhaps the USB ports kept alive external peripherals etc.

I find that XP Home has stupidly configured the LAN ETHERNET interface so my computer belongs to the WORLD, i.e. Realtek LAN has enabled :-
Wake-On-LAN after Shutdown, and
WakeUp on ARP/PING

I am happy to disable these two options just in CASE.
Please advise me, are there any other places in the operating system and or BIOS that also merit adjustment ?

If it is a KNOWN issue for the Acer to leave some equipment alive and discharging the battery I guess the only cure is to update the BIOS, but that cure is likely to be worse than the disease - ACER SUPPORT is useless.
Their main U.S. branch refuse to help because they cannot validate my U.K. serial number.
My local (U.K.) branch go no further than allocating a case reference number.

Regards
Alan
Since you mention a battery I'm assuming this is a laptop.

Why not just disconnect the ethernet cord?I was horrified to discover that Microsoft had applied this default,
but I am happy that I can disable the Wake-Up-on-LAN options,
or, as you suggest, disconnect the LAN cable.

My present concerns are that :-
1.
There may be non-LAN Wake-Up options that I should disable,
and I would like guidance on where to find them.
e.g.  could the scheduler cause wake-up from a shutdown ?
2.
Could the SHUTDOWN have failed, and left the BITS of hardware using up the battery, or only achieved SLEEP or HIBERNATION.

Regards
Alan