Sounds like you have picked up a virus or trojan file. Perhaps you didn't download LimeWire pro from the correct LimeWire genuiine home page.
Read as many of the "Sticky" threads at the beginning of these forums as you can.
Among them you should be able to find an answer to solve your current problem.
This LimeWire popping up by itself and hiding your taskmanager folder is a common problem that comes about through downloading a bogus file. There are so many jerks posing as genuine Limewire sites that you have to be really careful about who you give your money too. I hope this helps you in some way. but ususally most people find an answer to their problems in one or the other of those "Sticky" forum entries. (That is where most of the forum moderators have posted methods to solve problems like yours)
if you can't find an answer in one of them post back here and hope that one of the moderators (like Birdy) help you out.
Good luck!