aslam o alaikom

dear friends main skype ka letest ver use kar raha houn jo k aik masla kar raha hai software instal ho jata hai kabhi chal jata hai aur kabhi sirf us ki window aati hai leken us par jahan sign karna hota hai wo nahi aati pls kisi ko pata hai to bata dain
jub kabi chalta hai to aik do din main ye problem karne lagta hai pls help me thanks