Won't accept new password for appleID when trying to access my iCloud
I keep trying to access my iCloud on my mac but everytime I type in the password, it says wrong password for my appleID and then I reset my password and it still won't accept the new one. I have done this many times and still can't get access to icloud. This all started when I downloaded Mountain Lion. Someone please help. I have an imac 10.8.2, my software is up to date. Oh, I am not very computer savy so any help in lay mens terms or the idiots guide to apple would be greatly appreciated.
iMac, OS X Mountain Lion (10.8.2)