Another note: I tried installing CODMW2 and ran few terminal
commands (in return idk if they worked) and since then, this prompt
comes up whenever I launch CrossOver. What should I do?
http://img69.imageshack.us/i/promptx.jpg/
Hmm. That dialog suggests that you have either removed or broken the quartz-wm program that comes with Mac OS X.
That dialog shouldn't ever be necessary on Leopard. On Tiger, it was pretty common that folks didn't have quartz-wm installed, but with Leopard it comes installed by default. Apple changed things a bit with Snow Leopard, so that it's not installed if you turn off the installation of X11 when you install the OS. However, if you do that, you still don't get that dialog. Either CrossOver completely fails to launch, or it presents a different dialog suggesting that you install X11.
At this point, your best bet is probably to reinstall Apple's X11. You can do that using your OS install discs or download and install the latest "Combo Updater" for your version of Mac OS X from Apple's support pages.