My ACAD2000 has just started with an error during loading both achlnkui.arx & acEplotx.arx cannot find a dll or other file that it needs. Has anybody got any ideas I have re-installed Acad but I still get the same messages ??

Maybe, for those of us who are dummied, you can explain what you mean by:
ACAD2000
achlnkui.arx
acEplotx.arx
Acad
in reference to your questions?

ACAD2000 is Autocad 2000 and the other two are files that are loaded during the initial loading of the program

Do you have Service Pack 2 installed? or did you install Service Pack 2 as an upgrade on a computer that had no service pack, or service pack 1? Get any Windows Error messages such as unable to find xxx.ver ?

I have not changed anything on the XP side and this problem started all of a sudden a few days ago maybe through a windows auto update ??. I have found today that copying the two files from the Common Files\autodesk shared folder into the Autocad 2000 folder they now load up automatically. There is still another dbx file that I can't get to load automatically and have to load it manually but the program all seems to work ok after I do, so that problem I will have to live with for a while until I get time to have another go.