Thanks for the advice Satcomer; I'll get and run MacJanitor regularly - and I repaired permissions for the first time and indeed, even after my resetting of the plist files, it did find a couple of files to repair!
Much obliged and bye bye :)
Thanks Satcomer and Zammy-Sam; I'm up and running again! It did indeed seem to be the plist files. I think it was a problem with the QT plist file. Anyway all's very well now - could not have doen it without you guys, thanks! :D
Should I still be looking to regularly repair permissions...
Had my IMac running Panther for 4 months now; really great (apart from some early airport problems...) Been away for a couple of weeks, but hit a serious problem yesterday when I returned. (I have broadband & I regularly take all the software updates from Apple.)
Normally the Imac sleeps...