key validates, install/unlock fails

HELP! I have upgraded a vista to 7 home premium then to 7 professional successfully on my laptop. Now I would like to do the same on the desktop pc. I have upgraded vista to 7 home premium successfully but when I try to upgrade to 7 pro with disc as I did on laptop...I enter the key in the upgrade anytime window, it validates and starts the upgrade process, after a few minutes it tells me the upgrade was unsuccessful and to try again, which I did, it validated key and again the same thing...this is as far as it gets and I really do not want to do a clean install. How can I make this work. I have an HP Pavilion Elite m9660f PC.

When you get the unsuccessful upgrade message, close the box and then restart the machine.

BTW, one win7 license can only be used on a single computer at a given time so I hope you're not trying to use the same key more than once.

No install files needed.
Only the Upgrade key is need.
Anytime upgrade only adds-on the Programs & Features from version to version.
Windows Anytime Upgrade - How to
with Note for sp1 add

OK, Guys and or Gals,
I have went as far as purchasing a new key online, have manually rebooted as instructed when fail window comes up. Still no dice. I am still running windows 7 Home Premium. The first key I tried should have worked, I had bought the family pack so the key would work more than one time and on multiple machines...it did not install/unlock the professional version. So I thought it had been a couple of years since I bought the anytime upgrade disc multipac, so bit the bullet and bought an additional key online through the wizard. That key did the same thing unsuccessful install. So I manually rebooted yet again, still running the home premium. by the way it is the 64 bit system I am running. Do I need to install service pack 1? I have waited, because I wanted to upgrade before I installed the service pack since my key did not have the SP. I am in the hole here and need help, any suggestions short of clean install? I really do not want to do that and this machine is a fairly new machine, bought it with vista on it just 4 months before 7 came out and was on the machines. While I am here IF I HAVE TO DO A CLEAN INSTALL can I use the disc I have for the clean install and use the key I just bought when I am asked for it, how would I do that...since the new key has no disc? Thanks for all help in this matter.

Family Pack is Windows 7 Home Premium ONLY.

I understand that, I used the home to upgrade vista, I used pro key to upgrade from home...bought an additional pro key, both of the pro keys give me the unsuccessful message. I think I found a fix, am hoping so, in Microsoft solutions, that tell me to make sure I have all the updates in place and to stop everything in the start menu. I will try this. I do have a new pro key that is not on any other machine, it also does not work...will keep looking for solutions, as I DO NOT WANT TO DO A CLEAN INSTALL.

Success, installed the SP and the new key went in like a charm, no problems at all. Thanks for all of your help in this matter.