I used to have this problem too. After many things to try, uninstall and reinstall htc sync, etc, I've finally found the solution. I have read in some website it said we have to USE THE ORIGINAL USB CABLE which come with the htc phone. Then I've tried and it is unbelievable that it my laptop can find and sync everything immediately. After wasting my time for about 3 days to find out this problem, it's really work.