I fresh installed Ubuntu 10.10 back when it came out, and my laptop was suspending fine. All of a sudden, I can't get my laptop to suspend anymore. It's an HP Pavilion dv2-1110, but I don't think it's a hardware issue, here's why:

• It suspended fine upon first install. I haven't installed any new kernels since then, but I have installed tons of packages, so it's probably a package.
• The suspend and hibernate options disappeared from the shutdown menu. If I press my keyboard's suspend button (or if I close the lid) I get the following message:
• If I try the command pmi action suspend, I get the error message: Error org.freedesktop.DBus.Error.ServiceUnknown: The name org.freedesktop.Hal was not provided by any .service files.
• If I try the command echo -n mem > sudo /sys/power/state I get absolutely no output and no visible effect.

What might be causing this behavior? I thought a list of installed packages might be useful, but it's huge and I don't know how to post it here in collapse/expand mode or something.

EDIT:Just in case someone asks, none of the installed packages are kdm or anything like that (which would justify the lack of options in gnome's shutdown menu).