Why does rebooting nuke my wireless coection?

Hi all, I'm the same person in these two threads: http://ubuntuforums.org/showthread.php?t=2316533 and http://ubuntuforums.org/showthread.php?t=2320324 — my Acer laptop ruing Ubuntu really didn't want to get wi-fi but ultimately had to due to the efforts of many kind people.

What happens now is this: sometimes my computer crashes, and I do sudo reboot or am forced to hold the power button, but when I come back, my wireless doesn't work again. I go through the steps in the previous solutions and get back online in a while generally, although the last time there was a new error and I relied on a hint here to rename firmware-4.bin as firmware-5.bin.

I've had other functionality lost after a restart too, including lightdm and then the GUI, neither of which I've gotten back yet. It's really aggravating.

1. Why would it do this?

2. Is there some way to stop it? I.e., how can reboot safely if things start crashing, as they always do?