I was editing a tutorial to add more keywords and my ads are gone! http://designphase.net/ There was a file not found text where the ads were, and now they arent there at all. whats up with that?
Could it be that you have something like AdLogger installed recently? There is an option there to not show any ads to yourself.
I've had this happen when I installed Zone Alarm. Also check your firewall. Did you alter your hosts file in windows/system32/drivers/etc ? It should be empty by default. You can read more about that in my blog under my forum name.
My ads have been down on one of my sites for 3 days. Would google block the domain and not tell me about it? I have other sites on the same account and they all work... Strange