If you mean things like spyware, viruses, and the like, the system's clean -- I scan new executables, I run Spybot S&D, and so forth. If there's any malware lurking inside my machine I'll eat my dusty, sputtery casefan for a crunchy after-dinner treat. :P

About the only thing I can think of that could possibly be the problem if Limewire itself isn't, especially now firewall software is eliminated as a possible cause, is the VM itself. But it's Sun's most recent version (1.4.2), so it's neither out of date nor a weird, dubious 3rd party VM that may not implement the full spec. In short, Limewire performs poorly on a commonplace OS with the reference implementation VM and a decent hunk of hardware resources to draw upon. I hate to think how horribly 4.0.5 must run, if it can even get out of the starting gate, on the many older P3-266 128MB Windows 98SE machines still floating around out there!