Only logical answer may be in your re-format of, assume, single hard drive. Is every other application working except LWire? Check your partitioning and cluster size on re-formatted HD...single partition is simplest and cluster size depends on HD Gig size (if formatting done correctly cluster size is automatic). You did not supply system details as strongly suggested by LWire, so senior members can spot possible fixes...probably a Windows OS and proper format easy to check. If not able to do that, download 'Everest Home Edition' freeware, a very simple useful diagnostic app, which can show you new HD set-up. If OK, download latest Java runtime (think its 6-03), and then download latest version LimeWire (4.14.10 - FileHippo is good because it shows all versions). Then carefully go through ENTIRE LW configuration according to your specs. If this does not work, Reply with complete system info so senior members can help.
Luck, caseybob