spacebar problem

I have a six year old Intel Imac. My spacebar, hyphen, and apostrophe dont work (Im using a copied space). This started suddenly. They came back for a short while then stopped again. I live in the boonies, so theres no spare keyboard for me to try. Please help.

By the way, I tried with the alt/option key, and they still dont work.

It's probably gummed up with dust, or food particles, or whatever. Try cleaning it. See below.

I can turn my aluminum keyboard on my iMac upside down and tap lightly on the bottom and watch all the dirt and junk fall out.

If that doesn't work, get out of the boonies and buy a new keyboard. Or, order one from the internet either from Best Buy on line, or Apple. $49

Other World Computing also sells Apple keyboards.

Thanks.I.did.clean.it.Didnt.help.Took.it.to.a.computer.guy.in.next.town.He.tried.it.on.his.ccomputer.Its.the.keyboard.Tomorrow.I.order.a.new.one.
Thanks.anyhow!