Macbook refuses to connect ONE Win 7 Machine on Server

my macbook refuses to connect to one windows 7 machine on my server but connects fine to all the other PC's (Win7, XP and Win Server 2003,8). When i enter the password macbook says it is wrong i have even created few new accounts on that windows machine and yet no luck, this is rather weird pls help

also i tried connecting to same machine using other computers on the network and it work just fine.