Dashboard randomly stopped working for me. I look in the processes and its not even running. I have no 3rd-party/extra dashboard mods or widgets. Any ideas?
I figured out what as going on. Using information found here I deleted the com.apple.dashboard and com.apple.dashboardclient prefs in ~/Library/Preferences. This didn't work at first, but hearing varying reports on whether this worked I thought "I bet those it works for aren't on multi-user systems!" So I went into every account on my system and removed their dashboard and dashboardclient preferences, and PRESTO! It now works for everyone again.
Supposedly this is caused at time by account creation and/or account privilege modification. I am unsure why. Beware that following this process will remove any settings for any widgets you may have had on your dashboard, so it will need to be set back up.