Try this technique:
http://www.gnutellaforums.com/333278-post2.html
BTW do you have Alcohol installed? That can prevent LW opening. Also check which security softwares you have. Some spyware programs for example, think all p2p sharing programs are spyware & will prevent them opening, possibly even damaging them. You'd need to put LW on their safe list, depending on which ones you have.
I've heard AVG can also prevent LW opening.
If trying those things does not work. Set up a Test account. It's easy to do, easy to remove later. Then try running LW from there. At least that will narrow any problem down to your main account (most likely software conflict if that's the case.)