I've struggled with this one for a whole day, so here is both the problem & solution: After profiling an ASP.NET application on Windows 7 (x64), I exited Visual Studio (possibly a crash) and installed some updates which required a reboot. When I loaded back up the ASP.NET Web Application in my Visual Studio Solution was dimmed out, and the Web & WAS services turned out to be stopped. When I tried starting Windows Process Activation Service, I got the error "parameter is incorrect".