I'm on Win 7 x64 and had a lot of junk installed.  You name it, I probably had it.  Just from the top of my head, things like:  WebSphere Server, iis, MySQL Server, 3 different Visual Studio versions,  bunch of versions of .NET frameworks.  I got rid of everything and now I can run PCI ULLI at the lowest setting without a glitch.  I even played an H.265 video at the same time and browsed the Internet and no dropouts!
The best would be to disconnect completely (like Gary always says), but I need a connection on that computer.  Oh, I also shut off updates and disabled automatic reboot.
This may seem pretty obvious to most, but I just thought I would share my experience 
 
-Tom