Question : Problem: Acer Travelmate 8104 shuts down when no one is signed in

My Travelmate has been shutting itself off nearly every time no one is signed in.  There is nothing apparent in the Event Viewer.  There are no Windows error messages when I turn the machine back on.  It does not do this when someone is signed in.  (Users may be logged in, but if the machine is left at the "To begin, click user name" window, the machine will shut off nearly every time after a few minutes or hours.)  I experimented with being in and out of a login over several days, and it's very consistent.

The machine can be used all day long, with heavy disk usage or heavy CPU usage and it works fine, but leave it alone at the login window, and it justs turns off.  I tried killing Acer's epm-dm.exe power management process, and this didn't make any difference.  Acer hasn't been much help with this problem.  They suggested going back to a System Restore point when the problem wasn't occurring, but I need every application I have installed and it started doing this recently.  I haven't installed anything recently, anyway.

Answer : Problem: Acer Travelmate 8104 shuts down when no one is signed in

Acer isn't so good about documentation.
I did find this though. .. Not much help but some...

http://www.notebookforums.com/showthread.php?p=706009
http://www.smugmug.com/gallery/716040/1/31318568

Look at this pic. See the copper heat sink near the fan with the "M" stamped on it.
http://www.smugmug.com/photos/31318617-M.jpg
See those copper fins?
That's where "stuff" is going to build up.
If you can clean that well enough without disassembly then you should be good to go.
Do not blow into it. Use a vacum and maybe a paperclip in the fins to loosen things up.

Often the bezel between the keyboard and screen comes off exposing screws to the keyboard.

Sometimes keyboard screws come in through the bottom and many be hidden by installed drives, battery, memory, covers, stickers...

Some have these slide-tabs that work like a slide bolt.
The tabs are barely visible between and under the keys.
You push them with a small screw driver (or ?, I use a knife tip) and the 'bolt' disengages.