Darth Chaltab said:
I get that hacks would be against the rules, but why would legitimate serial numbers be?

And thanks, I may try that power-pack thing.

The problem with someone sending you a serial is that it might not work with your version. it all depends on what build your office version is. Each build version has a different batch of serial numbers that can be used. I came across this problem when i purchased a second hand computer and it came with a legit copy of Office but without the booklet and serial number. I tried to input one i wrote down from a box in my local WHSmith but it came up as an invalid serial.

You could try putting the hard drive in the other PC as Ziz suggested. I wouldn't use the PC for too long though because with all the diifferent drivers between computers could cause crashes, but if you can get office started then you should be able to find the serial so you can install it on the other PC.