I'm guessing the pack did not swell at all, if you are asking if the yeast was dead?
I know you've been brewing for a while, but there is a sticky on the forums that says fermentation can take up to 72 hours to start.
I would give it another day and check the gravity to see if it has changed at all before doing anything else.
I had a brown ale in a carboy that fermented over night. There were no signs of krausen, bubbles, swirling gook in the carboy. I was convinced I needed to repitch, but the guys at the LHBS talked me into taking some readings before doing anything. It had dropped 35 points in a day and a half with out giving any 'signs'.
Granted, this has not been typical, but it can happen.