How to replace bios battery at old Dell laptop Inspiron Series CMOS checksum bad (Error 0251 & 0271) - YouTube
Amazon.com: Synergy Digital CMOS/BIOS Battery, Works with Dell Precision M4600 CMOS/BIOS, (Lithium, 3, 200mAh) Ultra High Capacity, Compatible with Dell 077-A00, 0MR652, GC02001DR0, MR652 Battery : Health & Household