go to start---->Run--> type the word Regedit
~ Your windows Registry Editor will open,
~ Go to HKEY_LOCAL_MACHINE\SYSTEM\ CurrentControlSet\ Control\ Windows
~ Than please modify “CSDVersion” from “0×00000200” (SP2) to the Windows XP SP3 value of “0×00000300” and than reboot your system.
Now your Window has been upgraded to SP3 and you will be able to installed various advance softwares.
This is the easy trick which will bypass the information so that any program or software require SP3 (and if you have only SP2) would exactly work. So now enjoy; with all the gaming stuff.