I have a couple of laptops that users are unable to log into. They have existing accounts on their systems. They get past the authentication window, but windows will just sit trying to load their profile. I have reset their profile and that didn't do a thing. We have let the laptops sit for 18+ hours trying to login. It also happens to users trying to log into the system for the first time. Any suggestions?

OS: Windows XP SP3
Laptops: Lenovo T61
NW Client: 4.91 SP4