How to totally most machine freezes on Aspire One 751 running Ubuntu 9.10
date=2010/02/14
kernel=Linux aspire1 2.6.31-17-generic #54-Ubuntu SMP Thu Dec 10 16:20:31 UTC 2009 i686 GNU/Linux

1. Upgrade BIOS to version 3211 at least
2. Upgrade Ubuntu to latest package versions (in particular the kernel, graphics (poulsbo) and sound drivers (snd-hda-intel))
3. edit /etc/modprobe.d/alsa-base.conf and ensure the following lines concerning snd-hda-intel remain commented :

…
# Power down HDA controllers after 10 idle seconds
options snd-hda-intel power_save=10 power_save_controller=N
options snd-hda-intel model=acer

You should obtain :

…
# Power down HDA controllers after 10 idle seconds
#options snd-hda-intel power_save=10 power_save_controller=N
#options snd-hda-intel model=acer

⇒ Now you should not experience those nasty frequent random machine freeze…
(since I applied these patches on my system, I only got one suspect freeze after running it for more than two weeks - compared to multiple freezes per day before !)

one good test to experience machine freeze (before/after following this procedure), is to listen to music through deezer.com
try this with unmodified alsa-base.conf Ubuntu or Windows XP that is shipped by Acer, it will freeze very quickly !!