Symptom
After resetting PRAM, the computer's clock is off by up to 13 hours.
This happens if the computer can also start from Mac OS 9.
Solution
A Mac OS 9 System Folder is present
Start from your Mac OS 9 System Folder. Refer to technical document 106667, "
How to Switch Between Mac OS 9 and Mac OS X", for instructions.
Once started from Mac OS 9, start up from Mac OS X again.
A Mac OS 9 System Folder is not present
Use the Data & Time preference pane to correct the time setting. You can also use this solution if a Mac OS 9 System Folder is installed but you never start from it.