I have tried open office, but it will not open my ...

I have tried open office, but it will not open my existing ms word documents. So I have no choice, I have to get another set of ms word. There are no free trials offered by ms at moment, even though they advertise, they don't actually exist.
I still have my original 2007 msoffice disc, but because I changed computers, I can't use it because I threw out the box with the product code.