Anonymous asked in Computers & InternetHardwareLaptops & Notebooks · 8 years ago

cmos checksum bad system shutdown in 15 seconds?

i have an ASUS p5l-mx motherboard and i just got the stupid thing to turn on (long story behind it) i turned it on and it said CMOS checksum bad system shutdown in 15 seconds, i looked online for any and all possible ways to fix it; remove power cord then remove the battery and switch the CLR-CMOS jumper from 1-2 to 2-3 for 5-10 sec then put the battery back and replace the jumpers to 1-2 and plug the power in and turn on. i did that like 10 times and i also removed everything but the keyboard/mouse/monitor and still the same thing, how do i fix it?

MOBO specs: or this link for compatabilities

i hit anything i can think of to take me into the BIOS so i can fix it i even tried booting a flash drive with an updated version of the BIOS for that board by hitting ALT+F2 and start up, F8, CTLR+SHIFT+DEL, F1, F2, DEL, i replaced the battery 3 times with new ones, changed the IDE/SATA cables, changing the slot of my 512MB ddr2 ram stick, nothing works, the only thing it lets me do is TAB for post message display then i hit it again its back to the start up splash screen and hit it again its post message with just a logo at the lop left and no other text by that time it shuts down,

please help


you know what? i feel stupid...i did this trick on my dell xps 400 and it worked, but my ASUS board is still down, but still thank you for advice that fixed my dell XD

2 Answers

  • 8 years ago
    Favorite Answer

    doesnt sound right

    here is what you need to do

    disconnect your hard drives, you may be looking at virus messages.

    clear the cmos, ie (no need to remove battery)with power OFF and mains DISCONNECTED

    move the jumper over for 30 secs(to be sure its really clear)

    put the jumper back

    plug in the mains, wall switch ON, wait 15-30 secs for system to settle

    push the ON switch, the system should offer the message

    saying CMOS not set or similar, with F1 to Accept or F2 to run SETUP

    press F2

    choose LOAD DEFAULTS


    restart the system

    if the system is fine, reconnect everything, if you get therror back consider

    VIRUS infection as the reason for a STUPID misleading message

    also observe the following advice, if you think the message is valid

    1 the cmos battery must be showing 3.0V. anything less it needs replacement

    2 wrongly connected motherboard wiring can DRAIN the CMOS or corrupt it

    ...including the following reasons

    a) you have incorrect FRONT USB cabling. The PIN-outs are NOT standardised

    b) you have a low power supply, and you have excessive load eg GPU too powerful

    c) you have a misbehaving hard drive, it should be disconnected(i told you to do that)

    d) one of the peripheral power cables(eg if you have a floppy) is connected wrongly

    e) on your main switch block PIN head(eg PWR ON switch) you have wrongly

    connected something, so its shorting 5v to a weak ground causing corruption

    check all your motherboard wiring

    hope that helps

  • 4 years ago

    Cmos Checksum Bad

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