Solution
Hi guys,
I has this same problem and went nuts for two days trying to solve it. I had an excel file on my old laptop, then bought a new laptop, and put the same Office 2007 install on it (yes microsoft, I will remove the copy off the old laptop!). I could open previously saved files from the old laptop but, after i saved them on the new laptop, they wouldn't open on the new one, but still would on the old one. The file would open ok, but when I enabled the macros, excel would just freeze. It didn't make any sense as it was exactly the same office installation, so i completely formatted my new computer and reinstalled the whole OS and everything... still didn't work. After two days I was nearly crying!!
Anyway, getting to the point, just go to Microsoft and download Service Pack 2 for Office 2007. Its about 300mb, but solved the problem instantly. Hopefully this will save some grief for someone else!!