Probably from the limewire props file in the LimeWire (LW's user preferences) folder within Application Data\Limewire.
Click on thumbnail to enlarge the image
If you uninstall LW the LimeWire folder remains on your computer, unless you search for LimeWire within hidden files & folders (Application Data's hidden by default) & delete from there. That way, if you reinstall LW then your preferences are maintained from one version to the next.
The location of the LimeWire folder is...
XP: C:\Documents and Settings\your username\Application Data\LimeWire
Vista: C:\Users\your username\AppData\Roaming\LimeWire
OS X:
Users -> Account Name -> Library -> Preferences -> LimeWire
If you have more questions about why certain files aren't deleted while removing LW, try asking at the LW forum & a developer might be able to give you more info
Click on the blue link to go to the LW forum:
LimeWire Forums