Make sure disable Paging Executive first.
Now go to start menu and type msconfig in run. And then go to system.ini and then goto 386enh,then you add this string:"ConservativeSwapfileUsage=1".And then press ok.Restart your pc.....
Secondly make sure to make your paging size, just double of your quantity of RAM under virtual memory settings.
Now disable unnecessary startup programs from msconfig and then fire all useless services from typing services.msc in the run.
You should also make sure to have NTFS on all your hard drives installed.
Defragment as soon as possible. Go get Diskeeper Enterprise edition version 10 or above which one is available.It is perfect for all defragmenting needs. Run Frag Sheild once.
Use good quality softwares only with a very good antivirus like NOD32 or Kaspersky 6.0.
Try these and will surely help!