Why won't my itunes open?

Whenever I try to open iTunes it gives me the error message: "iTunes has encountered a problem and needs to close" and gives me the option to send a Microsoft an error report. Has anyone else encountered this problem with iTunes?? I've tried uninstalling and reinstalling itunes and that doesn't work. Is there some setting I need to change on my computer or do I have a hardware problem? iTunes is the only program I have a problem with.... I appreciate any help someone can give me. Thanks