i've had the same prob since up-grading to hi-speed.
got loads of help here.

first move your music out of the file it was downloaded to.
in your firewall make sure limewire is allowed.
dis-able daily & weekly scans. (you can do manually later)
you'll need to un-install L W.
then do a search on limewire and remove everything it can find, i also deleted the share file that my downloads went to. (just to make sure i emptied my recycle bin)

then re-install new L W (offline version).
do a search on limewire, check to see if you have something that says "LIMEWIRE.EXE-... C:\WINDOWS\Prefetch"
hopefully you'll be running. you will have to re-set your preferences in L W. this morn is first time i haven't had to re-install.

did i forget anything Grandpa? Lord?

P.S. if there's anything you can't figure out don't be bashful.