I bought my PC brand new in mid-2006. I'm currently dual booting Win XP 32 bits and Ubuntu Karmic Desktop. Over the last few days, when I boot up my computer, it tells me that my BIOS time is not set. I now have 2 choices for booting in:

  1. Windows first: I can safely get into Windows but the date now shows 2002/01/01 at 00:00. From there, Windows will not synchronise its time to its servers. I have to manually advance the date myself. I can also advance the date from the BIOS at startup.
  2. Ubuntu first: Since the time date is still set at 2002, the boot system cannot find my Linux partition. I can fix that issue by booting to Windows, set the date properly and the Linux issue will be fixed automatically.

The above two issues can also be fixed if I manually set the BIOS date/time manually when I turn on my computer. It's annoying to do that every single day since I shut down my PC daily.

Am I having an OS issue or a hardware issue? How can I resolve this problem?

Expanding on question

Now that I know it's BIOS battery issue, it looks like the problem can be solved on a regular desktop PC. Can the BIOS battery be easily replaced on PC laptops, MacBooks or Mac desktops?

  • A PC laptop might have you take apart the case and dig down to get to the battery. The Mac's, you might have to work with not only opening the case, but also the battery maybe hardwired into it. Good luck. – Chris Mar 12 '10 at 15:45
  • The battery-replacement issue should be a question by itself, I think. – Arjan Mar 13 '10 at 14:46

I would replace your BIOS battery. If this goes then your date is automatically reset everytime you power off your computer.

You can easily buy the batteries and they are cheap. e.g http://www.amazon.co.uk/CR2032-Battery-pack-Panasonic-Lithium/dp/B000I2JZLU/ref=sr_1_1?ie=UTF8&s=electronics&qid=1268433792&sr=8-1.

In my experience one size fits all in the desktop PC world. I cannot comment for Mac's or Laptops though as I've never changed one on these types of hardware.

Answering your expansion - I've never done a Macbook BIOS replacement but I know there is noCMOS battery for the iBook G4. Just a capacitor to supply the PRAM with charge during battery swaps.

Laptops - I've also never had to do a battery swap in a Laptop. I might open one up today to see.

  • Can you provide any links which shows how to do this? Is there one Bios Battery which fits all motherboard? Is it expensive? – Thierry Lam Mar 12 '10 at 15:20
  • 1
    @Thierry: You can consult your mainboard manual for that. – Joey Mar 12 '10 at 15:45
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    pctechbytes.com/repair/… – Joe Taylor Mar 12 '10 at 22:45
  • Some computers only use that battery when the 110/220/240 volts main power is unplugged completely. Leaving the main power connected (like to allow for wake on LAN, keyboard or mouse) sometimes/often also keeps the clock running. – Arjan Mar 13 '10 at 14:49

If replacing the battery is not viable, then you can use ntpdate to force the system to update the clock over the Internet.

There's also ntpdate.exe somewhere. I did use this method once on a client's computer.

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