MS Client For Networks

I have a windows 98 machine in the business which works perfect for everyone,
logs everyone on, runs login scripts fine but when one user logs on I get an
error message 'a network error occurred'

I have removed all the users local profile from the machine, changed his
password and removed his roming profile but still cannot get him logged on.
When he uses another machine however it all works fine.

Does anyone have any suggestions im all out of ideas?

Thanks.