I use Chrome now as I found I had too many problems with firefox and sometimes IE but chrome is great .. no more problems ..
if you do a disk clean you have to log in after wards as I think it deletes all your browing history.. not sure !
I use Chrome also Rainee and find it very good, when you clear your browsing history you do have to log in again, you can go into the browser and select the ones you want to stay but i don't bother too much hassle. And the same for Disc cleanup or if you use CC Cleaner.
Staying logged in is not wise, says the 'puter buffs'. If a hacker gets into that particular website your information is available to him/her, which makes sense, for that reason I log off from any forum.