Windows XP Activation Problem

I bought a XPS Gen 3 computer about two years ago. About one year ago I used the system recovery utility to restore my Operating System to factory settings. Then, about half year ago I had to reinstall Windows again, but when I tried to use the system recovery utility it didn't work. So I opend my Windows XP Professional Installation CD that came with my computer and reinstalled with it. Now, one day ago, I reinstalled again with the CD and everything went smooth. But then, today I was installing drivers when the "Activate Windows" message appeared, giving me 30 days to activate windows. I tried to activate through the Internet with my product key that's placed on my computer on a sticker, but it didn't work. So I tried to do it by phone, but the wizard doesn't give me any telephone numbers to call, it leaves them blank. So what can I do now? Is this caused becouse of reinstalling Windows soo often? How can I activate XP now?

Any help will be greatly appreciated.