I use XP & remove Java from Add/Remove Programs (within Control Panel)...not sure whether it's the same on Vista??

If you love your LW 4.8.1 & have the installer saved (I guess you do, to have been able to install it on a Vista PC)...you can reinstall that version whenever you like, providing the installer is saved. The newer versions of LW have a few more features & bug fixes, you can check out what's new in versions here
http://www.limewire.com/english/cont..._history.shtml

Other people have been able to run LW with Vista, though there have been issues with McAfee, Java & a few other things that nobody's too sure about yet...Vista's so new & it takes a while for all the problems to come to light, as more people use it we find out more info.

Have a read through the threads in this Vista section...then you'll see the sorts of problems people are having, how they're solved etc & it'll give you more of an idea about LW & Vista.