Resolved HDD changes in BIOS - PC won't boot

I've had this problem for about a week. The PC wouldn't boot because the BIOS changed the boot drive to one that wasn't each time I attempted to boot. I had to go into the BIOS, and return the boot drive to the top every time I wanted the machine to start up. I resolved the problem by changing the CMOS battery. It was that simple. The PC is only a bit more than a year old, and it's on most of the time, so the battery wasn't my first thought.

I'm posting this potential solution for anyone that may have a similar problem. Often other startup or clock problems are caused by a depleted CMOS battery.

 

When the HDD (or other) information in the BIOS suddenly changes or is no longer "set ", my first thought is the CMOS battery - even on newer machines. While it is not normal for these batteries to fail prematurely, until Man can create perfection 100% of the time, there will always be premature failures. Over the years, I have seen a couple (like, literally "2 ") that were bad, brand new out of the package.

That said, as you noted, the normal symptom of a weak or failing CMOS battery is RTC (real-time clock) problems where the date and time come up way wrong (not just off by a couple minutes) so it was a good catch on your part. Sadly, I have seen where folks format, reinstall the OS and even replace the drive before thinking of a $2 battery.

Your post is a good reminder to think small first, then move on to bigger suspects. Thanks for posting it.