Hi,
The 2008 / Vista memory mangement model is somewhat different from previous versions of windows. After you exit an application, 2008 retains the pages of the application unless the memory is needed by another application. This speeds launching because people tend to go in and out of the same set of applications. Previous versions of windows did this to some degree, but the memory was shown as "free" in task manager.
You now have lists of processes and services that are hanging onto the most memory per working set.
You can use this command, but it just clears idle tasks.
%windir%\system32\rundll32.exe advapi32.dll,ProcessIdleTasks
HTH
