Hi Georgi Filipov,
Are you using the online installer (about 1.2 MB file size)? If so, please try the offline installer, posted at the bottom of the Installation problems | Flash Player | Windows page, in the 'Still having problems' section. There are three different files and you'll want the one(s) that corresponds with the browser(s) you're using.
I went to your site and download it and it dose not install the box is blank task manager show its running but it not so what do I do now..
Please post a screenshot (The specified item was not found.) of the installer window and the task manager.