Where did you get your wallet from? Is it the most updated? Try using one of the older wallets, or compiling your own wallet on linux. The version that gives the least amount of sync trouble is 0.8.6.
One of the 0.10 versions breaks sync because someone mined 750 blocks with it, then switched back to 0.8 and started mining again, so I had to increase the super majority protocol to 7500 blocks. Try that and see how far you get.
And you can here give a functional version of the wallet and the current backup blockchain?
I am waiting almost two weeks and no support.