Apple ID password not working

I have imac Lion and when I recently tried to install updates, my computer will not accept my apple ID password. I am only user of the computer and I have tried everything to figure out why my password in not working. I also tried keychain and it will not accept. I have my password written down and the hint was set up when I used my password. Is there anyway to reset my password, or any way to contact apple to resolve this.
Thanks in advance

First try rebooting the computer.

If that doesn't work, then reset it here:

https://appleid.apple.com/

Thanks, but the computer would not accept my password to do a reset. I contacted apple and they instructed me on how to reset my password, without having my password. Everything working fine now.