Open registry by going to START-RUN and entering regedit. Navigate to the registry key that is
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SessionManager \MemoryManagement . Look for value of "LargeSystemCache". If available, do one of the following: If the computer is a workstation, set its value to 0.
If it is a server set a value of 1.
"Windows XP Tips: Improved Use of System cache"
Reference : techpraveen.com