It works for me on XP. Usually if LW won't open, it's a Java issue or a conflict with an antispyware program. You haven't installed or upgraded any antispy recently?? If so, make sure LW's on the list of exceptions/allowed apps.

I don't know how much you want to try the new LW beta. If you're keen you could try the Java 6 (JRE) beta with it (install Java first) & see if that makes a difference
http://java.sun.com/javase/6/download.jsp