Question : Putty on XP machine suddenly stopped working???????

I use Putty to SSH into my work LAN Server (Linux)...Putty has worked with no problem since the fist time years ago....all of a sudden I get Unable to open connection to [***] Unknown Network Error.   Nothing I do changes it.  Ran all spyware programs....Spybot , Spyware Doctor, Microsofte Spy..., Adware, etc. No viruses I am stumped???????????????????/ Tried Plink into the address....same error.  Everything else works....Browser, e-mail And even FTP App WinSCP...Ping works ???????????????????????????????

Answer : Putty on XP machine suddenly stopped working???????

Do you try using name, or ip address?
Try to delete SSH keys from PuTTY and reconnect using ip address.
Or you can enable logging (Session->Logging-> Log All SSH output) and give us more comprehensive info.
Did your WinSCP work fine with Linux using SSH?