Does LW get sent to recycle bin or just out-right deleted? I wonder if it becomes an invisible file. Do you have a shortcut for LW, try that next time & use the shortcut to open the actual LW program (not the folder.)
Which OS version do you have & have there been any recent updates for it? Update to the most recent java.
Restart the computer in Safe mode, try running ScanDisk, anti-av, & other utilities.
Scan with Hijack This. Also clean your Temporary Files. Do you have many items on the Quick Launch toolbar (which appears to the right of the Start button)? Clear them for the time being.