Well, use crlt&alt and press one time the delete button to open the task manager. Then go to processess and look for the limewire.exe process. Force it to end. Then use START>Search....>For Files and Folders....> to search for all remaining files and folders using the search query "limewire". Delete them all.
Then download the offline installer of limewire for your OS from here:
http://www.limewire.com
Try to install it. If it doesn't work then you'll have to update your Java. To do so Uninstall LW and all Java versions on your system. Reboot and then download the JRE offline installer of the newest Java version from here:
http://java.sun.com/j2se/1.5.0/download.jsp
Install it and reboot again, then reinstall LW.
