Windows 7 denying my activation code

So recently, I did a clean install of Windows 7 Home Premium 64-bit, and it has been just wonderful. But, just a few minutes ago, note that I did the install 2 weeks ago, it said my activation code for windows 7 home premium 64-bit is wrong. Now, the thing I have a problem with is that, I used the code that came with my computer. I bought the Dell XPS studio 7100 and it came with it, The activation is right above the service tag, and at first is registered fine, but now it is denying it.

What is wrong? How do I fix this? HELP

Is the code for 32 bit specifically?
If not, you can just use the phone in option.
control panel -> system
look at the bottom of the screen.

I don't believe the code is specific to the bit, but nonetheless, it won't take it. Actually, I am retrying the same code that is on my case (I did enter it correctly the first time), so hold on a moment. hmm, says activation is successful, but I would still like to keep this thread open. I am suspicious it will happen again, and I would just like to know what to do.

My guess is it just never processed properly on initial installation.
You should be fine now, the key basically becomes attached to your hardware configuration so now that it has taken it. You should be fine even if it rejects you again.

Under the EULA you are entitled to use 32- or 64- bit Win7 for each license, whether factory OEM or retail.

Are you certain you installed the exact same version as is on the COA sticker, and that you typed in the characters correctly as it is easy to transpose one or more.

If it fails again, use MS phone activation as activating with the Product Key on COA sticker changes activation method from OEM-SLP mass activation to OEM-COA using your individual Product key on sticker. This sometimes requires a call to MS to activate.
How To Activate Windows 7 by Phone Step-by-Step Guide

Dear friends,
As i have previously mentioned, i am a consultant physician to a few multinational companies in India! They were kind enough to give me a license out of the total volume licenses they bought from MS. One company gave me Win.7 Professional (One license)and the other,Win.7 Ultimate (2 licenses), one for my desktop and one for my laptop!

I initially installed the Win.7 Professional on the desktop and the activation was not successful! I un-installed it and made a clean install of Win.7 Ultimate and the activation went off as smooth as greased lightning(that too for 2 licenses). Can you kindly help me out to identify the problem area which led to win.7 Professional not being activated? I hope posting my query here is okay!

Regards,
Sreedhav

Was the Pro installation able to connect to the company's KMS servers to activate as a volume license must?