Dead yeast question.

Hello guys.

Quick question. I made a 1.5 L starter with 160g of DME and used a wyeast smack pack.

1) I noticed the smack pack didn't swell after 1 hour
2) I put it on a stir plate over night for hours and I see no signs of fermentation. Even when I shake vigorously nothing seems to be going on in there.
3) I have made starters before, this is the first time this has happened.

Do you think the yeast is dead?

Thank you

Take a gravity reading. That will tell you if there is, or has been, yeast activity. But if it's only been overnight, give it another day.