Thanks for replying, No error message on screen, at first I thought might have been the winpcap, but I have reinstall that, download the latest URL SNOOPER2 and getting the same results. This is what happens, when you lunch from the short cut (icon) a window blew open and then disappear. apply alt +tab you can see a window, but it is empty and will not appear on screen, seems to be hidden some how from viewing or accessing. I have use this software for a very long time without any issue.