you can go to exe you use to sign in right click go to properties
in target line "C:\Program Files\SecondLife\SecondLife.exe" --set InstallLanguage en
add -multiple at end to look like this
"C:\Program Files\SecondLife\SecondLife.exe" --set InstallLanguage en -multiple
that will allow multi log in so even if you have a veiwer running you can still log in
hope it helps
if your rebooting pc and still says your logged in then its in startup on pc
go taskbar select start where it says run type msconfig select startup tab and see whats starting up with widows as you log just uncheck sl viewer if its there good luck