If it doesn't restart by moving to a warmer room, test the SO₂ level of the stuck wine.  If it is above 80 ppm your efforts to restart will fail.  Test the sugar level.  If using a -5 to +5 hydrometer and the reading is below a -1.5 degrees or -2 degrees, then the wine is dry and not stuck.  (GettingStarted)  If the hydrometer reading is higher than a -1.5, such as a 0 reading or a plus 1 degrees, then there is residual sugar and one may attempt to restart.  It may also be lacking nutrient.  Add yeast nutrient in the recommended amounts, then rack as the yeast also need oxygen in order to start, even though the whole process of fermentation itself is anaerobic.  Racking will aerate.

If it does not restart on its own, make a yeast starter.  We recommend using Lalvin KIV 1116 or EC-1118.  These are strong yeast with good SO₂ and alcohol tolerance.  They produce a protein which is capable of inhibiting or killing sensitive yeast.   Make a quart starter using 3 parts of wine or juice and 1 part non chlorinated drinking water.  Rehydrate the yeast according to package directions.  This is important to do as it returns the yeast cell to a healthy, more functioning condition.  Rehydration in plain non chlorinated water should not be for longer than 10 to 15 minutes.  Add the rehydrated yeast to the wine/juice and water mix plus a pinch of yeast nutrient and one tablespoon of sugar (simple or corn sugar preferred).  Shake to aerate.  Oxygen is beneficial in getting the fermentation going. 

This starter will take one to three days to become active.  When active remove one half quart of wine from the carboy, reserve.  Replace this volume with half (quart) of the starter.  Add the wine removed from the carboy to the starter.  When the starter gets going again and if the carboy is not, repeat the procedure.  There will not be a violent fermentation as there is not a lot of sugar available.  Good Luck.