Ok. Let's see. If you still have the error about an older version of LW running, open Task Manager (ctrl+alt+del). If there's a LW process running, end the process. Try to install LW again & download the file from here: http://www9.limewire.com/download/LimeWireWin-full.exe

Save the file. Before you install LW, run this cleaner: Crap Cleaner

Can I just ask you - after you deleted LW's preferences folder (the folder named LimeWire), did you go through the LW setup wizard again? If you didn't have to go through that setup wizard - something went wrong & it wasn't deleted properly *eek*. If that's the case then it's worth your while trying to delete the folder again... it's so often a fix for weird problems

If you're sure that you did everything properly & still can't download a new LW, go to this thread. There's a link to download an older version of LW (post #6): Unable to run LIMEWIRE ('older version running' error)
Download that older version. If it installs without a problem then install the latest version that you downloaded earlier (it will remove the old version automatically). See how you go after that.

When you had FW up & running do you mean that only 1 file came up in your search results? If you're getting crappy searches (this is a problem for a lot of people right now), click on LW/FW's Connections tab (if you don't see a Connections tab, click on View > Show/Hide > tick Connections).

You'll see the hosts (ultrapeers) that you're connected to... right click on a host > remove. You can do that for all ultrapeers that you're connected to - they'll be replaced by new UPs. Does this help at all?

If your search results are full of spam, try this hostiles list - it might cut down on the amount of spam that you see: The TechNutopia Fullsize Hostiles List for BearShare and LimeWire

I know that this is no fun & we wish we could have one fix for everyone. It's just as frustrating for us as it is for the people with problems - we're volunteers who don't work for LW.