Since you are in a Hellenic situation with your install, I'm moving this to the Apothecary. You can reply to the topic there.

If you have the opportunity, try installing it on another computer. That should tell you if it is a bad CD issue or not. Then if it is not a bad CD, try deleting the MTW folder and trying again. Sometimes, stuff gets left behind during an uninstall.

Lastly, post your system specs (hardware & software) to help the techno-wizards troubleshoot the problem.