Help! My Worms has been crashing before it even loads to the main menu(due to my tweaking experiments). It gives me a black screen and after some time it shows a error message and then it closes. And when I try to reinstall it says to close any previous setup and close other applications.

Help me please, I use Windows XP and Worms 4 worked fine until that happened.

Try restarting the computer before re-installing, it sounds like W4's process might still be running.