A suggested beginning would be to get a good book about Netware. Even the older books, you can get very cheap (NW4, NW5) will have some of the basic stuff Marvin is sharing to get you familar with Netware.
As far as the upgrade, did you tell it to update the drivers when you did the upgrade? Most issues I have heard of going from 6 to 6.5 were driver related. Also, NW6.5 has some pretty different hardware requirements that NW6. Do you have enough machine to run it?
HTH
Ed