Keep your laptop accurate with a new battery.
All laptops, including the Dell Latitude C640, have several different power sources. The BIOS battery is a small, internal battery that powers the configuration memory (CMOS) and keeps the laptop's date and time accurate. If you notice that your Dell laptop no longer keeps accurate time, you may have to replace the Dell Latitude C640 BIOS battery. The battery is located underneath the keyboard of your laptop, so you will have to disassemble your notebook.
Instructions
1. Turn off your Dell C640 laptop and unplug any peripheral devices. Flip it on its cover.
2. Remove the screw located on the right side edge of the laptop. Slide the hard drive out and set it aside.
3. Remove all screws with a letter "K" from the back of the computer.
4. Flip the laptop over so that it is right-side up. Open the cover and push it all the way back so it lays flat.
5. Use a flat, thin screwdriver to pry off the panel above the keyboard. Set this piece aside.
6. Use the screwdriver to lift up the keyboard. Pull the keyboard up slightly to look for the single cable that connects it to the motherboard.
7. Unclip the cable holding the keyboard down and set the keyboard aside.
8. Look for the 6-cell BIOS battery, which is found just above the touchpad.
9. Remove the battery cable from the system board and pull out the battery from its "EMI shield."
10. Pull off any tape from the EMI shield to clean it off.
11. Thread the battery cable through the EMI shield and clip a new BIOS battery into it.
12. Reassemble the laptop by following these instructions in reverse.
Tags: Dell Latitude, Dell Latitude C640, Latitude C640, battery cable, BIOS battery, BIOS battery, from shield