Not able to browse inside Windows/INF
Many thanks for this divadrummer. In fact I inadvertently solved my problem when I did what iRiver told me not to - and loaded the up-to-date version of WMP. That presmuably did enter the appropriate file into the INF folder which made the driver happy once more.
As you say the support desk did not give good service. Those who replied seemed not to read my request for help carefully enough and the only response they seemed to have in their repertoire were "knee-jerks"; one size fits all, which may help the majority but but leaves the rarer specific probelm unsolved.
Good luck to the rest. RICHARD