How do I reinstall Compiz?

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http://askubuntu.com – Recently, I installed Ubuntu 12.10 on an old IBM computer, but when trying to log in, there is no Unity launcher, top bar, etc. If I wait around a minute or so, a message box appears that says "The application Compiz has stopped unexpectedly" or something along those lines. I can use the terminal (Ctrl+Alt+T) and have tried using CCSM and everything looks normal. I do not think it is the computers problem as the same thing happens when using "Try Ubuntu" on the live DVD, I think it is a corrupt download. No dialog boxes have borders. Does anyone know how to fix this? Also, this is my first tim (HowTos)