Slow pc fix / over clocking and exiting processes

Hi

I am running windows vista business on my computer, it is an :

Intel Pentium 4ht 3.20ghz
1gb kingston ram
Nvidia gforce 6200 gt 512 mb
creative sound blaster live

i have trouble playing games like fallout 3 and call of duty world at war

i have found that you can make them run better by over clocking your cpu speed a little i have done this from 3.20 ghz to 3.47 ghz also you can go to task manager and go to the processes tab and close unwanted processes like ...;

registry monitor
windows side bar
java updater
windows media player
windows media share
windows defender
program blocker
explorer.exe


i found after deleting these from my processes made my pcs performance better during game play when. when you close explorer . exe you will have no icons or taskbar at the bottom this is what explorer .exe is instead of using normal windows to go to application go to new task and browse for the exe you want to play/ use

Windows vista uses more processes than xp this will slow your pc down so by cutting back on the unwanted processes it will speed it up. when you have finished gaming and all just restart your pc and it will be back to normal if you cant find how to just type in explorer.exe in new task in task manager and then restart