I took this guide from my free eBook. If you want more guides (on making WoW Gold) then join my mailing list by going to the main page and enter your details in the subscription box.
First up, not everyone has a top-notch computer that can play World of Warcraft smoothly. So what I advise you to do is to open up Notepad and type in this code:
del C:\Windows\Prefetch\*.*/Q
Rundll32.exe advapi32.dll,ProcessIdleTasks
And save it as a .bat file (remove the .txt extension from it)
Please don’t start screaming “omg itz viruz”
For those who are super-paranoid, I’ll tell you what the .bat file does… All it does is deleting all your Prefetched Files leaving you with a clean session without memory-hogging stuff running even though you aren’t using it. It then kills idle processes on your system making it go faster as you have more memory to use 
To use this file, just run it before running World of Warcraft - in fact, you can use this before running any program that your computer may not be able to handle smoothly.
thanks man, this helps!