Answer to: incredibly slow and freezesIt's new, bring it to an Apple Store and let them fix it under warranty for you. Could be a hard drive problem, which is easy to fix. You could tell if you had another bootable external firewire hard drive to boot from, but you probably don't. Try booting from your OSX Install CD that came with the computer. Put the CDin the computer, restart the computer. As the computer boots up, hold down the "c" key on the keyboard to tell it to boot from the cd instead of hard drive. When you see the OSX screen come up, you can let go. If you can run through screens there (don't reinstall or you may lose some of your data) then maybe it is the hard drive. If you still have clicking and freezing problems while booted from CD, then you have bad problems that need to be fixed under warranty.
Answer to: keyboard replacement, Stock - BlackI don't think so. The new keyboards have spaces between the keys and the keys come up through the aluminum unibody. If it even fit in there, I think you would see the keyboard circuitry between your keys and probably get damaged easily.