SnowLeopard Login Freeze 2-5 mins

My MacBook Pro was running Leopard 10.5.8 and authenticating to an Active Directory domain (Windows 2003 Server SP2). I upgraded to Snow Leopard and have lost all Single sign-on functionality.

I have been speaking to MAC Genius at the store & then Apple care & they don't know why is this happening. I have done all possible troubleshooting adding & removing from domain. I am facing following problems

1.It joins the network / domain after hanging for 2-5mins.
2.everytime I go to accounts under system preferences it hangs for 2-3mins
3.if I lock my MAC and then go back in it hangs

I have around 14-15 Mac Book Pro in the company out of those 12 have been upgraded and having problem two which are still running Leopard are working fine on Active directory domain.

Anyone got any suggestion please help

It honestly sounds like a timeout issue. From the time that it's taking, it really sounds like a name resolution timeout (ie: DNS or WINS). You might want to see what got mangled in the settings when upgrading to snow leopard, and possibly remove it from the domain, make sure it's working correctly then go back and re-add it to the domain and see what happens.