I install the visual site designer last version on my new windows 8.1 of my new computer, worked fine but after restart app stop open ... how I can fix this ?

This can happen even if you are running as an Administrator, and it is caused by Windows very strict security settings.

To fix this configure the shortcut to always run as administrator. Here's how:

1. Right-click the shortcut icon, and click Properties.
2. Click the Compatibility tab.
3. Here, put a check mark by Run This Program as an Administrator.
4. Next, put a check mark next to Run This Program in Compatibility Mode For: and ensure Windows XP Pro Service Pack 2 is selected.
5. Click OK.

In the end your settings should match this:
http://www.coffeecup.com/files/predefined/run-as-admin.png

Thanks Adam ... its working.