precisely, it is not totally unresponsive, it has very low responsiveness for example, it takes many seconds before a window actually maximizes, when I click its taskbar button this behaviour does not go at all, it continues like this even if I kill via Task Manager the most memory hungry processes (firefox and opera that take each about 300,000 K of "Memory Usage" as shown in Task Manager) in Task Manager, CPU does not look too much loaded (it's below 5%) and PF Usage is 1,8GB (to be honest, even now PF Usage is 1.44GB but the system is totally responsive) after eventually trying to reboot, I get an error sayings that .NET BroadcastEventWindow does not respond to shut down and after that I get an error that explorer.exe does not respond to shut down, but both apps after waiting a bit, shut down themselves, without me having to force them after reboot the system is OK I made some research about .NET BroadcastEventWindow and it seems I must install .NET Framework 1.1, I did so and I will wait to see if this will fix that strange problem by the way, is there a method to free up "PF Usage" ?