Hey Blackbetty(etc!),

Yep I get that message about LW being unable to load old downloads if I switch versions, but I can still resume things from my incompletes (otherwise I wouldn't have suggested it). Have you used your computer's search to look for some of the file names?

Things shouldn't disappear...any chance that you (or someone else) accidentally deleted them? Unfortunately, most versions of LW don't send deleted files to the recycle bin. But...versions 4.13 onwards, these are Beta versions, do send files to the recycle bin if they're accidentally deleted. If you're interested, you can download the latest Beta (4.13.2) from the normal download page at www.limewire.com

How advanced were your incompletes? There are file recovery tools, but I'm not sure how much help they'll be with incompletes...it might be more trouble than it's worth to recover them & try to resume. You might be better off just downloading again from scratch. If you want to check it out, here's the link.
Deleting files from LW library - Don't!! File recovery advice

If you're really sure that you haven't deleted those files & nobody else has, I'd suggest an AV scan, just to check that you don't have a virus onboard