About login time and who's online

I am wondering what can be done to have more reliable login information:

Example, I am logged in and then it shows for others I am not since I left my computer and I am longer active on the site but my browser says I still am in the session or sometimes there is a person online and I cannot see that they are until I click various who's online links on the site - one will say not online and the next will say they are so I may actually have missed that person. Would like to also force the old session out if I move to a difference computer such as in Live messenger.

Where is the settings for login timeout?

I want to stay online all day so I can get instant messaging from the site instead of Live Messenger because I am admin or people will use the site since not everybody wants live messenger.

admin/settings/advanced settings/ "time period...."

Doh! I guess I won't forget that one and -1 would mean never ending...

untested but I think 0 would work better

I will try that, any idea on how to make the who's online more accurate, such as today I logged in with one account now that I have the timeout set to unlimited, and all day long I was in a second account and it said I was online with the other account as well....but not really as I could not send myself a instant message because in the profile I was not online but on the "who's online" section there I was...