I'd suggest reinstalling it.

So what caused it? If you have a spyware or adware utility then that might have scanned LW & done damage. There's some spyware programs that see p2p programs such as LW as having spyware whereas it doesn't. If that's the case, then put LW on that spyware's safe list. An example of such a spyware program that does damage is Pest Patrol.