[warra]

every couple of times i restart my powerbook, a message pops up saying that the date and time have been reset, so i change it to the current date and time, and click the lock to prevent any changes being made, but it all comes undone. I have leopard 10.5.1.

Any ideas?

[Art Vandelay]

Your PRAM battery is dead.

Also, the lock in System Preferences just prevents users from manipulating the prefs. It does not prevent the system from making changes or dead batteries from resetting the clock. It's not like the lock in Get Info that makes a file read-only.

[bradbissell]

Nevermind

[Art Vandelay]

The OP has a PowerBook which has a PMU, not an SMC. It doesn't hurt to reset the PMU or SMC of a computer, but this isn't a typical symptom of those.

[xi_hyperon]

As Art said, it's the PRAM battery. Replace it and the issue will go away.