Assuming you don't need/want Novell's NetWare Client Services installed, you can uninstall it, as suggested, by:
* Go start->network connections.
* Right-click Local Area Connection and select properties.
* Select the General tab.
* Find and select the NetWare entry from the list.
* Click the uninstall button.
* Go back and try enabling the welcome screen again.

Hope this helps,
John