Unchecked Norton AV Scheduler (liveupdate) in Extensions Manager because it was going haywire. Not sure if that was the cause but on rebooting was told Date was set before 1973 and this could cause problems. I'm then given three options, Server, Finder or Shutdown. To identify a time server or to lauch Finder I need a username and password but the previous owner of the machine did not provide me with this info so I'm a bit stuck! No discs came with machine so reinstallation not an option! Any ideas or suggestions?