Windows keeps asking to activate..

[628]

I just installed windows xp on my new drive, everything's working properly.

A tray icon popped up and said I have 30 days to activate. I click it. It opens a box that states I've already activated. (This is a version of windows xp that was on another computer, and I used the cd to install onto my new pc.)

Now, I didn't activate on my new hard drive, why is it saying I did? Can it be a problem in the future?

Also, everytime I start my computer it pops up asking for me to activate, and the same story again.

So how do I stop this?

Thanks in advance.

[kram 2.0]

Microsoft asks you to activate so that it knows that only one system uses any single liscence key (see EULA). Unless you purchased another liscence from Microsoft, you cannot install Windows on two or more different systems.

kram

[glc]

It is telling you that it's already activated on ANOTHER COMPUTER. To activate it on the new computer, it must be removed from the other computer and you have to activate it by telephone. Even then, if it's a name brand OEM CD that you used, you cannot activate it on a different brand computer.