I was following the instructions for setting up a SharePoint 2010 developer system at http://msdn.microsoft.com/en-us/library/ee554869(office.14).aspx and was near the end at "1.Install Visual Studio 2010 Beta 2 Professional."
The VS Setup process got to the actual "Microsoft Visual Studio 2010 Professional Beta 2" component and listed the action as "Executing action VsaEnv_Setup_x86_enu” and just stayed there. After about 12 hours I gave up and tried to cancel. The UI setup process still responds; the Cancel button pressed and and the widow moves around, but it doesn't seem to be responding to the Cancel request. It's not obvious what process I should kill; I guess "setup.exe *32" but there are two msiexecs there too.
I note that it got stuck on an "_x86_" action, but I've been installing everything on this system as x64. I thought I downloaded and installed the x64 version. I'll have to check that.
The system is P4 5GB RAM running Win7 Ultimate 64-bit.
Follow-up: I rebooted and attempted uninstall of VS2010 Pro and it too stalled, this time while "Executing action:DDConfig_Uninstall_x86". There's that x86 again.
One more follow-up: I uninstalled as much as possible then re-ran the web-based installer and told it to "Repair." It made it almost all the way through then at the same stage as above ("Executing action VsaEnv_Setup_x86_enu") I got a message box with a tilebar of "Vsaenv": "Cannot find one or more components. Please reinstall the application."