Hi,
 
First, make sure you have the latest version of the LimeWire software which you can obtain at 
www.limewire.com. 
Next load LimeWire, select connect in the file menu, and wait 5 minutes.  Is the search button still greyed out? 
Subsequent attempts to connect should be quicker as your LimeWire learns about the terrain of the network. 
Thanks, 
Avi