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

Do you have a USB keyboard? IF so, just plug that in.

No, i dont have. this is the only chance?
will be work with an usual usb keyboard,or i need only apple keyboard?

Thank you so much.

Any keyboard would be ok, I think, but it was just to get you some control over the iMac so that you can boot from the recovery partition. I'm out of ideas if you can't get any communication between the wireless keyboard and the iMac.

Using wireless keyboards, mice and trackpads, always have USB backups for installing software and troubleshooting.

Thank you so much guys for your help.
A friend of mine will bring to me a microsoft keyboard USB. if that will not work, i will buy the cheapest keyboard which not need drivers.
i will back to you today to tell ya if all works fine.

thank you again for your help.
Have a great day.

have fun you most likely will still have a issue you need a option key and wireless microsoft keyboards usually don't work like that you might need a real wired keyboard this is why i tell people go to your local thrift store and purchase a older mac keyboard like a g3 g4 or even the older white mac pro keyboard there cheap and thrift stores get rid of them on a daily bases

On the Windows-ready keyboard, the ALT key should be the equivalent of the Option key and the Ctrl Key is the equivalent of the CMD key. That's all you need to gain control of the iMac and boot from the CD from which you can then reinstall.