There's a point, if you have actually bought the software legitimately, then there is no shame in using a different serial to crack it. I have tons of dodgy serials for software i have actually paid for, because you never know...
All my serials have been got from using WinMX, the excellent file share utility, by searching for words such as 'Microsoft' 'office' 'crack' 'hack' 'serial' et c.
I have several for office 97 that i have never had to use thankfully, i would post them here, but that;s just silly really, and would pave the way for forum abuse and general silliness.
Maybe you should see if you can install a copy of office 97 from another person's cd? again, you should be able to find a CD image using WinMX of an M$ office distro, and if you have a cdwriter, then Bjorn Stronginthearm's your uncle, as they say.
This is of course, illegal, but as M$ have told you already, if you install Office on yr new machine without paying for it AGAIN then you are breaking your contractual arrangement with them anyway.
In for a penny, in for a pound, i say...
If you can bootleg a copy of Office, i think it's fair since you have already paid for it once, and you will ultimately only be using it on one computer anyway! Go for it.