if you have problem to Sig In Yahoo Messenger(YM) .
1st you check the internet explore(IE)is working correctly. most of the time it don't work. (but Firefox,chrome,Gtalk,etc..etc.. are works correctly)
so go to IE ->Tools->Internet options->Connections->LAN Settings->
Check Automatically Detect settings and uncheck other options.
(See image below)
Now IE and YM will work fine...
1st you check the internet explore(IE)is working correctly. most of the time it don't work. (but Firefox,chrome,Gtalk,etc..etc.. are works correctly)
so go to IE ->Tools->Internet options->Connections->LAN Settings->
Check Automatically Detect settings and uncheck other options.
(See image below)
Now IE and YM will work fine...