I've searched a lot but was hoping someone could help point me in the right direction.

We're running OES2 SP1.

A few days ago, all of a sudden users who are running Windows7 can't connect to the server with the Novell client, or if it does work, it only works for a few minutes and then disconnects.
I've tried several versions of the win7 client, and even the Vista client.
I am manually entering the IP address and context of the server in the client.

Nothing was changed or updated on the server before it stopped working.
I'm not sure where to start here..
Every machine running XP continues to work perfectly.

Any help is greatly appreciated, Thank you.