Give us the URL, sometimes ads don't show up sometimes maby because of a problem. Did you change anything?
I would say yes, your banned. Try logging in to your account, and you'll know for sure. If you still can login your not banned.
Probably would warn you first, so make sure to check your spam box appropriately and such.. you dont want to miss the warning emails... but if you are doing something like invalid clicks, they've been known to ban right away and you cant blame them if there is valid proof.
If the entire page can't be displayed (not just that ads aren't showing up on it) I'd say you've got some other sort of problem than being banned. Unless the site was such that not only was it banned from adsense but also that your hosting provider took it down.
If you contact them and your account still not get restored again, there might be a backdoor for you to get into adsense again! Sign up at blogger.com and tata, you can have an adsense account again. hope that helped
If your banned then it will say "page cannot be displayed" type error wherever the adverts should be, I think. Hopefully theres just an error with the adverts or connection or something
No, there will just be a blank spot. I've seen this before, not on my sites but on sites that have gotten themselves banned for one idiotic reason or another.