Windows Genuine Advantage Plug-in?
 

What is Windows Genuine Advantage Plug-in? I just installed it from the Microsoft site and wondered if its best to uninstall (where do I find it?) or keep.

i.e. Internet Explorer and Windows Media Player 11. Not too sure what else it affects though.
If your Windows is a legitimate copy, then you should be alright. If not, then get rid of it as quick as you can. Normally you can uninstall these from the control panel, but I don't think that you can with this one. Might be able to disable it somehow though.

It allows you to download certain major updates from Microsoft after the plug-in confirms that your operating system is not pirated in any way. I'm not sure that there is a way to remove it completely.

I got buy computer at Best Buy and they installed Windows XP so my XP is not pirated, I just want to get rid of it now. So can anyone help me?

It's not dangerous. You don't need to get rid of it.

The only thing to be aware of, is that you could have your install of Windows crippled if WGA hits a false positive and decides your legit copy is not "genuine". This would usually involve annoying banner instructing you to buy another copy of Windows. They do have a support forum here if you run into this down the road. Microsoft has also introduced this for MS Office 2003, so I would keep that in mind before you update Office. Further information about WGA can be found here

But this won't be nearly as bad as Vista WGA, which will severely cripple your installation at any time, limiting your session to minutes and only allowing IE to run if it suddenly decides your license isn't legit (it will revalidate on a regular basis.)

is normal if installed it but if you are still want to remove it try WgaOga 3.0