replacing cmos battery hp lap top

barry till, you can follow these instructions:"

Before removing the RTC battery, follow these steps:

1. Shut down the computer. If you are unsure whether the computer is off or in Hibernation, turn the computer on, and then shut it down through the operating system.

2. Disconnect all external devices connected to the computer.

3. Disconnect the power from the computer by first unplugging the power cord from the AC outlet and then unplugging the AC adapter from the computer.

4. Remove the battery.

5. Remove the following components:

a. Switch cover and keyboard (see Switch cover and keyboard on page 64)

b. Palm rest

c. Top cover on 14-in models

Remove the RTC battery:

1. Position the computer right-side up with the front toward you.

2. Remove the RTC battery from the socket on the system board.

Reverse this procedure to install the RTC battery.

Or you can download the maintenance and service guide from here. Hope this helps, good luck.