Your laptop's CMOS is a small battery-operated chip on your motherboard. It stores temporary data important to your laptop's basic performance. This primarily includes your ThinkPad's date and time settings. Resetting your ThinkPad's CMOS is a useful way to troubleshoot laptop system problems. The best way to reset your ThinkPad's CMOS is by disconnecting and reconnecting the CMOS battery. Many computers require complete disassembly to access the CMOS battery. Fortunately, ThinkPad's are designed in such a way that you can access the CMOS without any disassembly.
Shut down your laptop, disconnect the AC power cable and close the LCD screen.
Place the laptop face down and rotate the laptop its front edge is facing forward. Locate the battery pack in the upper right corner of the motherboard. Press the battery's release button. Remove the battery from the laptop. Though this doesn't seem necessary, it serves as an added precaution against causing electrical damage to your computer.
Locate the memory compartment cover in the center of the laptop's bottom casing. Remove the single Phillips-head screw securing the memory cover. Remove the cover and set it aside.
Locate the CMOS battery inside the memory compartment situated to the left of the RAM modules. Gently pry the battery out of its compartment with a small, flat-head screwdriver. Disconnect the battery cable from the motherboard.
Leave the battery disconnected for eight to 15 hours. That is how long it takes for the CMOS to manually reset. Place the battery inside its compartment, and re-connect the battery cable to the motherboard.
Replace the memory compartment cover and its retaining screw. Place the battery pack inside its compartment. Press down on the battery until it snaps into place.
Things You'll Need
Small, flat-head screwdriver