I bought Skyrim and originally installed it on my sisters computer because mine was not present. I now have my computer back and I have been trying to install it again on this pc, but when I type in the product code, it says that it is already in use by a steam account and that I have to "retrieve account". So I retrieve my account, and it stops installing. I have looked everywhere for help, but I can't figure it out. Pleaseeee help!
Do you mean computer or Steam account?
If you mean the latter (which I assume you do, because otherwise you shouldn't need to enter the product code again), I have bad news: You cannot register the same game on two different accounts, and you cannot transfer it now that it's registered.
You can install the game on different computers, but you need to be logged in the same Steam account on both.