Could you please clear something up for me (that you said in an earlier post):
both computers can talk to computer A if A is not plugged into the router.
If Computer A is not plugged into the router, then how do the other computers communicate with it?
If you still have this entry in your Registry (and you can't locate the file in your LAC Properties), then that means you must have Uninstalled/Removed it incorrectly. If you are positive that you do not need any sort of Netware connection on your computer, and you can not locate NWLink IPX/SPX in your LAC, then you can remove this registry entry.(*Note: Before you remove this entry, please create a Registry Back-up).
Run LSPFix.exe again, however this time check 'I know what I'm doing' and then select the nwprovau.dll file, and press the right arrow (>>) to send it to the Remove section. Scroll down and click 'Finish>>'. Restart your computer, and test your Connection.