IIS: can only install FTP& Gopher, not WWW

On two different machines, one NT4S one NT4WS, when I install IIS (ok, Peer Web Server on the WS m/c), I can only install the FTP and Gopher components not WWW!!

We checked carefully that we crossed the WWW box in add/remove, but in the next screen where you specify the directories, the WWW section at the top is greyed out. We're logged in as admins.

By 'we' I mean me and the Admin, who's flummoxed too. He wonders if somewhere at the corporate level (we're a multinational) the ability to install WWW has been turned off since that virus scare some time back.

Anyone got any ideas please?