Windows XP Activation problem

After a computer has been Syspreped (mini setup was selected and then resealed), I am unable to activate Windows XP. I power up the computer, go through the mini setup screens, key in the Microsoft Product key from the lid of that computer. Once the desktop appears, I am prompted to activate Windows. I click on the bubble and select activate over internet. I then get to the screen that states Checking for Connectivity and that remains for ever and ever. I did confirm that the computer is connected to the internet by launching a web browser and typing in several web sites.