Trouble with Windows XP Service Pack 2

In your How To Protect yourself from malware it says that you should have the Windows XP SP2, im having trouble downloading it. I've done the things they say in the get ready for SP2, but it still doesnt seem to work. I have a Fujitsu Siemens comp. There are no specifications for it with SP2. Is it really necessary to install it?

 

First I link to the Get your pc ready for windows xp sp2. Then i do the "Before you install Sp2". I've used the ad-aware software. Then I try to check the PC manufacturer updates for SP2, but my computer (Fujitsu Siemens) doesn't have any specifics on it. I already have a backup harddrive. Then I go to "How to Install SP2", and then I check for updates on windows update, but SP2 doesn't show, so I guess my computer isn't ready for it. That is as far as I have gotten. Please help me.

/Berra

 

Thank you for your help, I've now installed Service Pack 2.
I have another problem with a software which won't go away. It's called Zyxel something, its keeps slowing my computer down and wan't it gone. Please help me.

 

It was a wireless internet utility driver and i'm not using it any more and I've already uninstalled it. However, when I start my computer it shows up in the activity thing in the right corner and it takes a while for it to disappear and then my internet connects. There is no error message of any kind.