Lawnmower will not start !?

Can someone help me out... My lawn mower has been in the shed all winter, I took it out the other day and checked the gas and oil and filled them so they're perfect. It's a 6.25 horsepower lawn mower with front wheel drive, I pushed the gas button like 5 times and tryed starting it but it just keeps cranking and doesn't start ? What's going on ?