I brewed a 5-gallon batch of a cream stout on 12/30/12. It was an extract recipe and i boiled 2.5 gallons on the stove. The yeast is WLP013. It fermented actively and I moved it to a secondary fermenter after a week. Kept it in the secondary for about 2 weeks. I bottled on 1/20/13. When i bottled I boiled 2 cups of water with 1.5 cups of Briess Golden Light DME plus 1.5 ounces of corn sugar - I added that touch of corn sugar just to ensure good carbonation.. I kept the bottles in the warmest room in my house - which is not so warm at this time of year. It's probably 66 degrees most of the time and the thermostat sets back to 63 during part of the day and at night. After three weeks I tried one of the beers and it tastes very good but there was no carbonation. I took one of the two cases of bottled beer and put a heating pad under it for the past week. The heating pad is on its lowest setting. I thought one week would be enough to generate a little bit of carbonation so I put one in the refrigerator for 24 hours and then opened it but there is still no carbonation at all. Anybody have any ideas? I had a batch once in the past that didn't carbonate and I never figured it out. This is not a real high gravity beer, so I don't think the alcohol killed the yeast. Any help is appreciated.