Make sure that it's not set to run on system startup. In LW tools > options > advanced > system startup. Untick 'run on system startup' & apply.

If LW still keeps opening after that, you've probably got a virus. Follow the "viruses on the network" link in my post #2...there's a lot of info & various fixes within that thread. If you like, try the other fix I've posted there as well.

If none of these work, or you don't feel confident to try, get some free computer help from Norbiesworld. There's a link to his site in post #2.