Where do I find this Key?

HKEY_local_machine/software/microsoft/windows/currentversion/run/optionalcomponents/lmail

 

Word, which came with my machine, now reinstalls every time I try to open it, says I need the above HKEY, and won't install even though I have the CD that came with the computer.

If I'm lucky enough to find it, can someone tell me how to load it?

I'm desperate.

 

Thanks