Imac not start, wirless keyboard reset I have a problem with an IMAC 27'

1: the osx was corupt so it wasn't boot anymore.
2: i changed the batery from the keyboard so, i canot use the keyboard for startup key combination to reinstal the operating sistem

All i want to do is to reinstal the operating sistem (i have the original cd) but i can not do anything. any command i try to do on startup, dosn't work because the keyboard was reset (i think). I put the cd in and now i can not eject because ... guess what... the keyboard not work, of course.

so, what can i do? 

thank you very much
Thee is nothing you can do with wireless keyboard at this time.

Get a USB cable keyboard, from friend or from store.