Avast Internet Security 5.0.677 Final fails to allow the following roughly 50-75% of the time...
Firefox 3.6.9 (plugins are set to load into seperate threads as per default settings) -> DivX Web Player plugin. Google Update plugin, Picasa plugin, Flash 10.1 plugin, Silverlight plugin, Yahoo Application plugin Fails to load in a sandbox.
SRware Iron 6.0.475 -> Flash 10.1 fails to load in a sandbox.
Opera@USB Portable 10.61 -> Flash 10.1 succeeds to load in a sandbox all of the time!
Not even going to bother trying IE 8 even in a sandbox.
Windows 7 Pro x64 (UAC is disabled)
AnVir Task Manager Pro 6.3.1
Process Lasso Pro 3.84.7 (firefox.exe and plugins.exe have been excluded from ProBalance Restraints)
Internet Download Manager 6.02 beta