What's the error you're seeing when you try to open LW?

What security programs are you using? Some antivirus programs will see LW as a threat & remove it... maybe that's why you have to keep reinstalling LW? This thread has an example: Why do I always have to re-download Limewire?

Try adding LW to the list of allowed programs for whatever security programs you're using. If that doesn't help, try temporarily disabling your antispyware & see whether that helps.