when I start lync application "lync has stop working"

The root cause of this could be any number of things. If repairing the installation and removing the cache Lync user profile don't help, use MSCONFIG to perform a selective start-up in order to try and determine what's causing the problem.

Check your event log to see if there's anything useful in there, although you're most likely only going to see some unexpected application termination errors.

Please also ensure that you're running the latest version of the Lync client update.

Kind regards