When was the last time that you have defragmented your HDD?
Did you install the newest Java version using the JRE offline installer after you uninstalled both LW and all other Java versions and rebooted the computer after uninstallation and new installation of the Java?
Did you try to install LW in Save Mode?
Did you change the compatibility mode of LW to Windows NT or Windows 2000 by right-clicking the LW icon on your desktop, choosing Properties>Compatibility?
Disabling any Security Software installed on your computer prior to the installation process mentioned above might also help....