First you must set the CPU Priority setting tweak.Using 'Regedit', go to this location:"HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\PriorityControl\" and set the "Win32PrioritySeparation" to "38"
The last adjustment is to set the "Launch folder windows in separate process" setting by opening the "My Computer\Tools\Folder Options\View -and tick the "Launch folder windows in separate process" box.
Window XP will open any new window(including program) in its own memory and in separate process priority.(increase stability and speed but use much more RAM than before)
Note:
Sometimes this 2 tweak can cause unresponsive keyboard and mouse in Counter-Strike.