Upgrade new PC from Windows 7 Home Premium to Professional?

Awhile ago, I bought Windows 7 Professional and installed it on my computer. Recently, that computer died unexpectedly and I bought a new one that came with Windows 7 Home Premium installed on it. Since getting a new computer was unexpected, there were things I needed to get installed right away, so I just started installing it on the version of the OS that was already installed on the new PC. Now that I have a moment to go back and upgrade it to 7 Pro to take advantage of the features I want/need, this is appearing to not be an option, or at least not an easy one. The only options I'm seeing are to do a full reinstall or to do a Windows Anytime Upgrade which requires a separate license key. I have enough software installed now I really don't want to have to reinstall the entire machine again. Plus there were some applications that came for "free" on the new PC that I'd like to keep, but reinstalling would mean that keeping those apps also was not an option. And it seems stupid that I'd have to buy an upgrade when key when I have a full version of what I want to go to. Any suggestions? Is my full version DVD of 7 Pro a paper weight now?

Thanks in advance for any help.