Imac logon issue/virus?

Password Virus?

Have a new Imac running Panther bought in November - have been receiving regular software updates online - on January 1 another update began, Quicktime 6.5 and a "Security Update" - upon restarting unable to enter password - other keys on the keyboard are fine but letters dont appear in password dialogue so unable to logon. Typing a letter makes the cursor in the dialogue box stop blinking, but no letters appear. Have tried booting from Panther disk but cannot cannot despite Apple tech support off phones. On their advice have returned machine for servicing as still covered under warranty. Anyone have any idea what happened? Have heard about a windows virus like this....

Have a new Imac running Panther bought in November - have been receiving regular updates - on January 1 another update began, Quicktime 6.5 and a "Security Update" - upon restarting unable to enter password to logon - other keys on the keyboard are fine (disc eject, audio etc) but letters dont appear in password dialogue so unable to logon. Typing a letter makes the cursor in the dialogue box stop blinking, but no letters appear. This is the case with original and wireless keyboards. Have tried booting from Panther disk but cannot cannot despite Apple tech support on phone. On their advice have returned machine for servicing as still covered under warranty. Anyone have any idea what happened! Have heard about a windows virus like this....